It's the main thing that the fandom is based upon, but what a lot of furries have in common is being friendly and open towards others. It's by no means a requirement but for whatever reason furries tend to be very inclusive. We're all here to have fun after all, regardless of nationality, gender, age, political views, financial status or whatever else that usually separates people.
Fursuiting is wearing a costume of an anthro animal (kinda like school mascots
). It's most common on conventions and gatherings, but some furries do it privately for fun.
The requirement is owning such costume, which isn't chat cheap. But again, it's definitely not a requirement of being a furry, just another way to enjoy it.
It's a pretty decent drawing. I guess you're from the side that prefers animalistic humans more than anthro animals but it still counts of course.
I hope I cleared some things up