These are great questions!
I'd been fascinated with the idea of the Gorch characters since I read about them when I was ten. Back then (1984) there wasn't much information or visual references for the characters besides them being very ornate creatures and considerably more adult in theme and humor. So to a kid, that sounded fascinating.
When I finally got the see the characters (In Jim Henson: The Works) when I was 18, I fell in love with the designs. And when I began seeing the sketches in recent years the whole thing just came together for me.
I guess because the Gorch characters seem so far removed from anything else Jim had done, and because they're very much in my humor sensibility, I felt very inspired. It's not like anyone else was rushing to use these characters for anything, and only old guys like me or big, BIG Muppet nerds (again, like me) know of these characters, so I figured I should dust them off and breath fresh life into them.
I love King Ploobis. I really do identify with him as a personality. He is the brash and obnoxious partier I was in my mid 20's, but he's also a misunderstood ox of a guy who never seems to get it right no matter how hard he tries. That's who I am today, who I was then and who I'll always be, albeit hopefully a tad more successful in my efforts. Ploobis is the Kermit of this strip, the glue that holds it all together. He'll always have a hand in every adventure that comes out of this cartoon, no matter what cameos I bring in or how disconnected they seem to me (They're all Muppets, afterall).
I DO intend to do flashbacks! I have a Sam and Friends flashback in the works, plus I want to do a couple SNL flashbacks. There's a gag I'm working on where Ploobis, as seen in the first strip, kinda likes the idea of going out in a blaze of glory (i.e. party hard and leave a bloated corpse). Eventually he's going to start riffing on Belushi, saying how Belushi stole his act (they were similar personalities, after all), and he'll work on his own tell all biography similar to the one written by Bob Woodward just after to Belushi's death.
Anyhow, I have a great many ideas I'd like to try, all for the simple love of the Muppets, and particularly The Gorch characters. Thanks for the great questions!