I think they should keep Gibbens as the second LB for now, until Tavai comes back. At that point, Tavai probably takes the spot. Then Ellis and Gibbens are depth pieces for specific situations. Obviously we hoped Ellis would take a step forward but it hasn't come together.
Bench Stevenson for a week, then work him in here and there as the third RB. Henderson ~40% of snaps, Gibson ~35%, Stevenson ~25%. Perhaps elevate Jennings for a couple weeks and see if he gives you something. Realistically, they're missing a true "power" back. But those guys aren't usually that hard to find. Maybe start sniffing around some practice squads.
Douglas just doesn't have it, at least in this offense. Start giving Chism some reps, and also sub him in for Jones as a punt returner here and there.
I don't really have a problem with Austin, he's just a CB4 at best being forced to play too much. Until Gonzo gets back, rotate him and Woods. When Gonzo gets back, neither of them are likely to see the field much anyway.