its been a while since I read super hero comics, so I messed up the character is from The Runaways (who came out the same time as young Avengers) the character Karolina Dean (
http://marvel.wikia.com/Karolina_Dean_(Earth-616) ) is a lesbian and a vegan. The Runaways trades I think are still able to be found in Digest editions, which were 6.99 a while back when I was reading them.
One of my favourite vegan characters is from a comic called
The Freshman. He like all the characters are a bit of a joke (its a humour comic) but I always liked the fact that he was very hardcore about his veganism, and told people to 'shut the fuck up" often. He's called Green Thumb and has the ability to talk to plants.
Also just as a "check this out" there was this three issue miniseries called
WE3 by Grant Morrison and Frank Quietly which tells the story of lab experiment animals running away from a lab.
One day I'm gonna get going and review a ton of vegan/AR comics.