I've always figured that people's animagi form are the same as their patronus, mainly because I think the only person we see the form of both for in canon is James Potter, and they are both stags. With that in mind...
Barney - is a labrador. Big, loyal, enthusiastic, he bounds up to people and (metaphorically) licks them, and barks loudly but without any malice. He makes a tiring pet but he has a nice waggy tail :-)
Mel - is thinking too hard about this, going through the characters in Animal Farm to decide on her favourite. I think actually I want to make her a monkey, because I can think of several monkeys in animal fables that suit her.
Lee - wants to be a tarantula, and since I can't think of anything better for him, that's what he'll be. Fluffy and cuddly, but not always that nice.
Luke - wants to be an ewok. Sorry, Luke, they're not real. I think he's probably a lemur instead. I can see him hanging on things with his tail.
Valentina - is definitely some small sort of bird. A bluebird, maybe? I always think birds are so delicate because of their fragile skeletons. She also has the tendency to take flight at the slightest indication of danger. And she sings nicely.
Yakov - now YAKOV is more like a sloth, Patricia :-P Actually I think he's a pig, because although he's lazy and slobbish and loves his food, if you actually clean him up and put him somewhere nice he can be quite intelligent.
I actually have a meme I've been thinking about too, which I'll probably put up at the weekends if that's cool with everyone.