Hmm. . .random trivia about Keats. I love collecting trivia on people I'm interested in and Keats is one of them, to be sure! So, here are a few thoughts off the top of my head

I don't know if you need to cite sources in your paper--all of this trivia can be found in most Keats biographies somewhere.
Early in his career as a poet, Keats tried to "dress the part" as many young artists do. He experimented with growing various moustaches and was often seen in an outfit that looked something like a naval officer's uniform.
Keats was known to be pugnacious as a boy and that attitude carried on into his adult life to a certain extent. Once, he discovered a butcher's boy torturing a kitten in an alleyway. Keats tried to get the man to stop torturing the kitten and they ended up in a fight that lasted for some time and resulted in the butcher's boy being dragged away. Now, butcher's boys were known to be big and brawny. The fact that Keats was rather slender and *very* short shows what a good fighter he was.
Keats loved Claret wine--especially from Chateau Margeaux.
Keats enjoyed playing practical jokes, as did many of his friends, especially Charles Brown.
When Keats and his friends got together to play a "concert" (i.e. they all pretended to be an instrument in the orchestra and, with their voices, "played" a song together), Keats always played the bassoon.
Keats was notoriously terrible at reading his poetry aloud. He never did his work justice (so says his friend Woodhouse).
I don't know if this qualifies as trivia. . .but you could always tell what concerned Keats most in his life--it was the person or issue that he never spoke about. So, when Keats clammed up on a subject, you know that's what he's concerned with most.
Keats hated to dance--most probably because his face was about the same height as most women's breastline and considering the high-wasted, low-collered dresses women wore back then. . .dancing for him could have been quite embarrassing.
Keats's favorite flower was the violet.
Keats's favorite actor was the famous Shakespearian actor, Edmund Kean.
I believe Keats's favorite season was Spring (that's just something I deduce from how he speaks about it in his letters)
Keats had reddish-brown, curly hair, had a low voice and spoke in a faint cockney accent (so they say).
Keats was just over 5 feet tall--pretty short, even for his day.
One of his favorite plays was King Lear and Shakespeare was his favorite playwrite. I'd say that Keats considered Shakespeare his literary father-figure.
Keats did not like having his birthday celebrated and often forgot it, himself.
Keats REALLY enjoyed punning. Probably more than your average poet
Well, I'm getting a headache trying to come up with any more trivia,

, so that's it for now. Again this is all off the top of my head--I'm sure his biographies would have much more information. Cool question, though!