The days quickly passed by peacefully. Since all Chad's meals were prepared by his chef elves, he only left the cupboard to go to the toilet. Two full weeks of playing video games that he had not played since he was a child, was his idea of a nice break. Because he had Jedi mind tricked the Dursleys to leave him alone until they received his Hogwarts letter, Chad did not have to act like a retard and hand his own letter over to Vernon, Petunia got the mail instead.
On the 24th of July, 1991, shrieking and cries of outrage were heard throughout the house. Soon there was thumping on his cupboard door, but he merely leaned out and hit them with another compulsion to keep ignoring him until the place was flooded with hundreds of letters. He also made sure they didn't try to move him to Dudley's spare bedroom because of the address it was mailed to, much better to use it as ammunition later. They continued to receive a letter every day addressed to Mr H Potter, The Cupboard under the Stairs, 4, Privet Drive, Little Whinging, Surrey.
After the dodgy job of boarding up the letterbox, letters begin to appear rolled up inside eggs and down the chimney. That was until the 29th when thirty or forty letters come pouring out of the fireplace. Uncle Vernon has had enough, he packed everyone into the car and drove around for hours. They finally end up in Cokeworth and stay the night in the Railview Hotel in an attempt to outrun the multitude of letters that persisted in arriving for Harry.
The effort was in vain, as about one hundred messages were delivered to the hotel the following morning. Vernon Dursley disposed of them, then left the hotel and heading for a hut on a rock out on the sea in his latest attempt to escape magical mail. Throughout the event, Chad made sure not to touch any of the letters just in case and had his elves collect every one of them that came to be hidden under the house. Vernon only ever destroyed copies created by his magical minions. He also reinforced Dudley's joy at being 'normal' and that he was glad 'Harry' was now the freak.
And then, on a dark and stormy night, in all his glory, Hagrid made his entrance. Chad honestly loved this bit in canon, as it showed just how much of a loveable doofus the half-giant was, he just needed to force Dumbledore to throw away the loyal/brainwashed servant so Chad could make use of him. After three crashing booms against the door to the shabby hut, it fell to the ground, and the nightmarish scene of a monstrous figure entering to a terrified family occurred. If Chad didn't know what was happening and didn't have his magic, he probably would have been packing his dacks as well.
"Sorry about that." Said the clueless half-giant as he lifted the fallen door back into place.
"I demand that you leave at once, sir! You are breaking and entering!" Quite rightfully declared Vernon fearfully, while pointing his double-barrel shotgun at Hagrid.
With total disregard of the law and general mood of the room, Hagrid just bent the barrel of the gun while insulting the quivering mound of flesh. "Dry up Dursley you great prune!" This cause Vernon to fire both barrels in panic and blast a hole through the second floor of the shack.
"Boy, I haven't seen you since you were a baby Harry, but you look just like your father!" Hagrid boisterously bellowed, correctly identifying Chad since he wasn't hiding behind a pillar, and Dudley was not a chubster thanks to his meddling and the power of magic.
"You know me?" Chad asked, playing along. He was currently illusioned to look like the skinny, bespectacled slave with a scar on his head that Mrs Figg reported to Dumbledore.
"Well of course I do, I was a friend of your parents! Oh, that reminds me, I got something for you. Afraid I might have sat on it at some point, but imagine it will taste fine just the same! Baked it myself, words and all."
"Thank you!"
"Not every day that your young man turns eleven now is it!" After handing over a cake that actually looked edible, Hagrid sat down in front of the fireplace and magically lit it with his illegal wand.
Continuing his performance as a clueless eleven-year-old seeing magic for the first time, Chad made all the right noises of astonishment before asking who the f*ck this magic-wielding stranger was.
"Excuse me, but who are you?"
"Rubeus Hagrid. Keeper of keys and grounds at Hogwarts. Of course, you would know all about Hogwarts."
"Sorry, no. Is it a place where sick pig farmers live?" Asked Chad, taking the piss.
"Sick pig farmers! Blimey Harry, it's a school for magic! Didn't you wonder where your parents learnt it all?"
"I'm afraid all I was told about my parents was that they were worthless drunks and layabouts that died in a car crash."
"What!"
While Hagrid ranted and raved at the Dursleys for being trash, Chad had the cake swapped out for one prepared by his elves. Who knew what potions it had been laced with! Since Chad never let the cake go, Dudley never ate some and got a pig-tail in retribution, although Vernon did take a slap to the face from a meaty half-giant hand when Chad continued to 'stir the pot.'
After the shouting and threats were done, Hagrid then went about making himself comfortable. In true ruthless fashion, or maybe just oblivious to fundamental human interaction, Hagrid proceeded to spend the night in the tiny shack with the family he just terrorised. Chad thought it was absolutely hilarious, but couldn't work out which category Hagrid fell into, bumbling and harmless or ruthless and cunning. Either way, he made the rather unfortunate mistake of sleeping near a Legilimency expert.
The next day saw the long commute from the island off the coast all the way to London to get Harry's shopping for school done. Before they left, Chad made sure that he was dressed in rags that would shame him when he was seen wearing them, first impressions were important, and he wanted to be seen as a slave.
During the trip, Chad made sure to ask basic questions of the magic world, just like any other curious eleven-year-old would. There was a good chance that Dumbledore would be scanning Hagrid's mind and Chad needed it to be as untouched as he could for his plans to work. Too much interference with Hagrid's memories would be a warning sign if investigated carefully.
Arriving at the Leaky Cauldron, Chad was ready to put his best foot forward, greeting everyone politely and shaking their hand if they offered. He was not a clueless child to be overwhelmed by well-wishers and did his best to appear humble and polite. The perfect image of a poor orphan angel. If anyone took note of his clothes, they didn't mention it or show any signs that they did. A pale young man made his way forward, very nervously. One of his eyes was twitching.
"Professor Quirrell! Harry, Professor Quirrell will be one of your teachers at Hogwarts." Said Hagrid.
"P-P-Potter," stammered Professor Quirrell, grasping Harry's hand, "c-can't t-tell you how p-pleased I am to meet you."
Chad had been wondering if this universe followed the book or the movie since planning for this day, and with Quirrell shaking his hand without flaming death, it seems it continued to follow the book. So far it had, as characters looked different than the movie actors. Which was a shame, Chad had been hoping to have Hagrid force them into a private room for breakfast if Quirrell had been carrying Voldemort around with him. Instead, a team of house-elf ninjas would tail him to wherever the spirit was residing after he failed to rob the bank.
Quirrel was only possessed after he fails to steal the package from Gringotts. Not taking his failure well, Voldermort decides to share Quirrel's body to make sure he doesn't make any more mistakes. But it was far more likely he needed to leach off Quirrell's soul to gain strength. Not to matter, everything was still ok. Instead of plan A, Hagrid made his apologies, and they left to enter the Alley. Hagrid also continued to fill in the blanks about the fame of Harry Potter as he opened the path to Diagon Alley.
It was time to see how Dumbledore would solve Harry's financial problems. They walked down the Alley admiring all the organised chaos while Hagrid pointed out the shops they would need to visit. Walking through the Gringotts entrance, Chad once again mentally scoffed at the clever riddle that didn't even phase school children before they successfully robbed the place. After Hagrid offhandedly insulted the goblins in a not so quiet voice, they arrive at a teller that was supposedly the Head Goblin in charge of all goblins.
"Ahem. Mr Harry Potter wishes to make a withdrawal." Stated Hagrid.
"Ah. And does Mr Harry Potter have his key?" The creepy sharp-toothed gremlin asked as he peered down at Chad.
He was unsure if the goblins would see through his elf made illusions, but wasn't too worried even if they did. After all, Hermione could get away with being polyjuiced, and Hagrid seemed to have no problem using Harry's key without any identification in canon, why would they cause him problems now. Not to mention that they didn't bar wanted criminals or report illegal artifacts stored in vaults.
"Oh, wait a minute. Got it here somewhere. Aha! Here's the little devil! Oh and there's somethin' else as well. Professor Dumbledore gave me this. It's about You-Know-What in Vault You-Know-Which." Hagrid replied after patting himself down, seeking the key. He then handed over the key, and a letter addressed to the Head Goblin.
"Very well."
Everything then continued as it did in canon, except Griphook took them to a different vault that Dumbledore obviously set up for Harry. With everything looted from Godric's Hollow by Boppy, there was no way that Dumbledore could access the Potter vaults. And since he was trying to introduce an abused orphan of a rich and famous house back into the Magical community, he could hardly have 'The Harry Potter' create a loan like other needy students. He would be skinned alive if anyone found out.
Since Hogwarts tuition was free thanks to the Ministry of Magic, all he needed to do was create the illusion that Harry had a trust fund by creating another vault under his name. Maybe it would cause too many problems to just ask for a new key or lead to unwelcomed questions. Like who was his godparents, current legal guardians, or why the Potter's last will and testament were not executed.