Do you keep your FeralHeart business secret from friends in real life?
Mostly no.
My closest friends know quite a bit about FeralHeart, and my roommate at school is also familiar with my involvement with it (since she sees me playing on the game or working on the forums all the time xD). So, if you spend enough time around me, chances are you'll know a thing or two about FH.
While none of my real-life friends play FH regularly anymore, I wouldn't have a problem if they came back. I tend to wear my heart on my sleeve, so if they see some different sides of me, sometimes that's alright. I love to share my artistic sides, but usually it takes them to come to me (or where I spend time) to express or show it to them.
Not to say I go around flaunting FH around, though. xD Only if asked will I bring it up... Tentatively.
However, my fursonas, Allegra and Linger, are a different story. Generally I refer to them as "my avatars" to those who don't understand the furry-like community we have, where a fursona is very special and unique to each individual on varying levels. It's easier to say they're my "face" in a community, but they go much deeper than that. I will generally only open up to others about what Allegra and Linger mean to me, if the one asking has a fursona of their own (or if for some reason they just have a genuine interest). Those with fursonas are more apt to understand the connection you have with your characters, in my eyes.
Would you respond if someone called you by your fursona's name in real life?
If someone called out the name Allegra or Linger in real life, I know I'd turn around and look with surprise. xD I actually have a coworker in real life whose name is "Ally," and so every time I hear someone call her, I can't help but double-take, before remembering that no one there knows I also go by Allegra or Alley. Or Linger. Or White. (Fricking names I just kshaknjbsh).