Harry was unsure if Neville would be able to talk reason into Ron and stop him from leaving the Gryffindor common room after curfew, but it didn't really matter. The main objective had already been completed and gaining a small favour of Longbottom would just be a bonus.
Harry merely wanted to introduce himself, gain a positive impression and then engineer a situation that would create more contact so he could slowly influence Neville into his minion. For a shy boy with no friends, having the chance to be tutored for a week would be second to just getting to talk to someone and make a friend!
And if Ron happened to insult Neville and drive him in his direction? Then that would also be a welcomed result to his initial plan. Having Neville confront Ron and publically oppose him would only create a barrier between them, especially with Ron's already negative opinion of Longbottom. Even if Neville somehow talked sense into Ron and saved him from humiliation, the damage would already be done.
Amazingly, there was no new exciting gossip of Gryffindor first-years being punished for breaking curfew. Still, by the dejected look on Neville's face as he sat on the end of the bench, visibly separated from the other kids, it was clear that Ron was just not caught in the act. Which honestly amazed Harry how such a doofus could have escaped Argus Filch and his bloodhound cat. Though avoiding a Squib and a cat when you had magic would be extremely easy if you had a brain.
Draco had really dropped the ball on his end. Who did he know that would be willing to help him because he was obligated to and hated Gryffindors? Oh, only his godfather Severus bloody Snape! If Snape had been in on the plan from the get-go, he would have thoroughly humiliated the rulebreaking children and then dished out the maximum punishment!
Must be all that ambient magic in the air dumbing down people again, it was honestly scarier than the Dark Lord! To so thoroughly affect your mentality and decision making, scared the sh*t out of Harry. If his personality changed, was he still him? Fair enough, he was not the greatest example of humanity, but Harry still liked how he turned out. The thought of becoming the same as canon Draco Malfoy or Voldemort made him check and recheck his personal idiocy shield in fear.
Talking the dejected Gryffindor outcast into joining him and Hermione in the library every day turned out to be even easier than he thought it would be. Neville was practically begging him to be allowed to join once Harry mentioned it. With his terrible potions class antics, it would have probably had the same result even if he wasn't lonely. It also gave Neville and Hermione a chance to become friends, them not really having interacted since she dragged him all over the train in search for his toad.
Things were going nicely. There was no maniac trying to kill him like in canon, the student's fanatical interest in him had lowered to an appropriate level, and his new minions were listening attentively to any opinions or suggestions he had. Even the Ravenclaws stopped knocking on his door after he dropped a few hints that he hated to be disturbed from his only private time.
Finally, after three months of school, Harry felt it safe enough to visit the most important place in Hogwarts without being interrupted. The Room of Requirements, otherwise know as the Come and Go Room or the Room of Hidden Things. When one of his elves popped him into the room directly, Harry was amazed at just how much junk was packed into the place. And the size of the room itself was significantly larger than you would expect from a place that was hidden on the seventh floor of a castle.
It was about seventy metres wide, by a hundred and fifty metres long, and was jammed packed of all manner of items and furniture piled on top of each other. How people found anything without using magic would have to have been because of luck or plot armour. Apparently, the Room of Hidden Things had special protection that prevented a Summoning Charm being used in it, meaning people had to physically find what it was they were looking for.
This was certainly the case when Hermione attempted to summon Rowena Ravenclaw's Diadem but failed, although this may be because the Diadem was a Horcrux. They actually didn't test it on anything else which was a bit stupid. Harry pulled out his wand and cast the spell on a cloak that he saw across the room that was draped over a chair. He wanted to know all the limitations of the room.
"Accio cloak!"
The cloak knocked the chair over as it zoomed across the room to his waiting hand. Fortunately, the chair was not holding up one of the precariously balanced piles of junk. Otherwise, it would have been slightly dangerous if it started a domino effect.
His misconception about one of the Room of Requirement's rules debunked, Harry decided to clean it out so he could start testing out the others. But gaining the Diadem was the primary goal.
"Boppy!" He called.
"Yes, Master?" The immaculately dressed head-elf asked as he appeared out of thin air.
"You know that underground storage facility I asked you to prepare before I left for school? Gather a team of elves and transfer everything in this room there, and please sort it by item type. But be careful of a diadem hidden somewhere in here, it is a Horcrux and needs to be brought to me as soon as it is found." Harry commanded.
Seeing his head-elf staring uncomprehendingly at him, he couldn't help but clear up the misunderstanding before the eager little buggers got to work.
"You are not sure of something?" Harry asked.
"Ah, yes Master. What's a diadem?" The house-elf asked.
Which was fair enough, Harry had never heard of one before he read Rowling's books.
"It is very similar to a tiara."
Seeing the continued questioning look on his elf's face, he could only sigh. Harry was not blaming the little guy for not having heard of obscure women's jewellery or knowing what it looked like. He just wished he wasn't having this conversation and that Rowena had made an artifact that wasn't gendered specific. He could hardly look manly in a diadem.
"It is a piece of woman's jewellery that is like a dainty crown to be worn on the head. It will have jewels on it and look like a silver circle." Harry explained.
"Very good, Master. We will get on it right away!" His most loyal minion enthusiastically replied before popping away.
Harry looked around at all the things stacked together and wondered what he was going to do with the majority of it. Just a quick glance was enough to see that he would have no need for most of it as it was junk.
Broken and damaged furniture (mostly chairs, tables, and various cabinets haphazardly stacked)
Thousands and thousands of books (either in tottering piles or in bookcases)
Fanged Frisbees.
Chipped bottles of congealed potions.
Corked bottles whose contents still shimmered evilly.
What looked like dragon eggshells.
Several rusting swords.
A massive, bloodstained axe.
An enormous stuffed troll.
The broken Vanishing Cabinet that he had the partner of from Borgin and Burkes.
Hats, jewels (including a trunkful), and cloaks.
Many cages in various sizes, including one with a 5-legged skeleton in it.
A chipped old bust of an ugly warlock.
A few, heavy broomsticks.
A banjo.
A set of dominoes.
Various metalware (including cauldrons)
Various trophies.
A mask.
Various portraits and empty frames.
Suits of armour (some disassembled)
Various textiles.
There really was a fantastic amount of variety in the junk stored here, and that was just what was in his immediate vicinity. If Harry didn't have an army of elves to magically manage it for him, it would have taken him ages to sort through it for anything of value. He had to know what he was looking for to summon it after all. Seconds later, thirty elves appeared and started shoving things into magically expanded trunks.
Their speed and dedication was amazing to watch, so he walked over to the chair he had knocked over from before, and sat to watch the gradually disappearing junk piles. Harry wasn't sure how the magic behind the room worked and preferred not to leave until everything was cleared away. Since it was only ten o'clock in the evening and he now wasn't always disturbed by fans, he had plenty of time to watch the magical housekeepers do their thing.
But before he could get comfortable, Boppy appeared in front of him with Tom Riddle's Horcrux, the elves worked fast! Now there was only Riddle's Diary, and Hufflepuff's Cup left to recover for their tasty soul pieces. Harry was actually more curious about the Diadem itself than the actual Horcrux, as it was said to be able to increase the wearer's intelligence.
"Good job, Boppy! I'm going to take care of the Horcrux and then examine the Diadem. Make sure to reward your elves for their work after they finish cataloguing everything and notify me of the results." Harry excitedly said as he took the Horcrux from his elf, ignoring the pathetic compulsions coming from it with his iron will.
Voldemort's main soul had long since been absorbed without consequence, so Harry was eager to expand his soul once again and increase his willpower. Having an untainted magical artifact of legend would also be brilliant.