Regarding species: just choose something that appeals to you.
Don't worry about changing your species later on if you find something else that works better, either; lots of people do that. And for that matter, there are also lots of people who don't have a species of their own in that sense but who rather have a number of different characters among which no single one really stands out as a "personal furry" or something similar.
As for what will go on at the con... well, there's lots of SIGs and stuff, of course, and other events, and also socialising, talking, hanging out, having fun, and so on. ^^
