MC Dies in his world and reincarnates in Harry potter as an animal
(Options: Phoenix, Owl, Cat, Snake, Rat)
The story should be written in the perspective of both Harry and the MC so there wouls be more material to write about
I personally think that a phornix would be beat since you can teleport and shit like that.
One day Harry Potter finds an egg in a park and decides to take it home and hide it from the Dursleys
Later on the egg hatches and it turns out that it is our MC who is a phoenix.
Once the MC reincarnated he decided to bond with Harry Potter and help him.
Make it evil/very manipulative Dumbledore so you can give the MC a purpose which would be protecting and helping Harry Potter avoid being manipulated or used by other people.
I feel like whenever there is a story with an animal MC then the story should have a lot of comedy in it.
Follow the plot but change it up a bit. Personally i would put Harry in slytherin to make it even more interesting.
For the pairing i would make it Harry x Ginny, if you make Dumbledore manipulate the Weasley then it could make some nice drama.
Make Ginny be the only one that doesn't blindly follow Dumbodork and place her in Slytherin too for even more drama.