Derek as the DM would be funny in a chaotic way for all of 20 minutes, but I see it going 1 of 2 ways. Either a) he runs out of material really quickly because it took him an hour to write and he thought it would take an hour to play, leaving the game to fall flat, or b) the plot is absolute nonsense to follow and everyone gets bored halfway through. I don't think he'd be all that enjoyable.
Sally is obviously the most experienced, but also if she's DMing we can't spank her or use her as a projectile weapon, so that's a bust. I actually think Zoey would make a great DM if she sat down and tried - she's very creative but also knows how to go with the flow, so I think she could write a really solid little adventure and then be adaptive enough to run it so long as she had a general idea of what she was doing.
As for the party, Sally is an obvious must, and I think Jill's fine to keep with us. Part of me does want to see how Bella would play, but I also suspect she'd manage to bulldoze every problem by just thinking about them logically in ways that a bunch of college students wouldn't really think of. I think Sage would be fun to have play, so long as she's having a good time. It doesn't really seem like her kind of game, but I think she'd be down to join with friends; so for our purposes, we'll just have to assume she and Zoey are on good terms whenever this happens. For the final member... Riona, I guess? She loves the arcade, so pen and paper probably isn't too tall a task for her. I think she'd at least be open to it.