Fun thread. Ok, a few answers on my end...
1) The Bull that posted to Shadowtech is technically not the same Bull as the "Best Ork Decker YOu Never Met". I was playing Bull by that point, but Target: UCAS was my characters Debut as a Shadowtalker (I won a contest on the old ShadowRN mailing list, along with Spike, Granite, Fro (Adam Jury's original online handle), and one other person... Kumquat maybe? It COULD have been my character, I was playing when the book came out. And I always claimed that it was me.
2) A fair number of characters were based on real characters. Talon was Steve Kenson. Josie Cruise was Jon Szeto's. Bull was mine. Slamm-O was Fred Hoopers. Winterhawk belonged to one of the assistant Developers. Pistons was Elissa Carey. Half the characters I ever put into anything I wrote were either some of my secondary characters, friends characters, or friends online Nicknames. But, a lot of time, they were either jokes, or just random names pulled out for fun. I know in one of the SOTA books, Jon Szeto used a bunch of GI Joe names to fill in for merc posters.
3) An "In Character" chat was done once, during one of the Live Chats that CGL did for a while. I'd actually love to see something like that done again, or do up something like that on the forums here.
4) I'm going to end up using some of the Season 4 Missions Conatcts and NPCs in the UV93 threads for shits and giggles, and I wouldn't be surprised to see some talk about events going on in Missions pop up there.