(Just read the bottom portion of this post.)
Here's a handy flowchart I made:
Alright, we'll use this flow chart then...
"I have one friend who loves anthros and considers himself a furry even though he doesn't draw, write, read, or participate in much furry things. Is he still a furry?"
*Checks chart* Nope.
"I have another friend who is interested in the adult side of the furry fandom but doesn't have a fursona or any interest in writing/drawing furry things. Is he a furry?"
Hmmm... no.
"I know a person online who loves anthros and draws them all the time, and even has a sort of fursona but doesn't consider herself a furry (hates furries actual =/ ) Is she a furry. "
And... nope.
Wait, something's wrong here.
...Okay, here are my actual answers:
1. Yes.
2. Yes.
3. Nope. (Denial, anyways)