There's really no strong indication. The way things are right now the top 6 is probably some arrangement of Kane, Hertl, Meier, Couture, Labanc, and Donato.
And the bottom 6 will be made up of 6 of Marleau, Nieto, Gregor, Noesen, Kellman, Gambrell, Sorensen, True, Suomela, Handemark, or maybe Blichfeld or Bergmann.
Personally if there are no more moves to add forwards and this is the group we run with, I would like to see:
Kane - Hertl - Donato (I don't love Donato on the first line but I'd rather not have him and Labanc on the same line)
Labanc - Couture - Meier (Meier probably deserves to be on the first line, but see above)
Gregor - Suomela - Noesen (I irrationally like/have hope that Suomela can bounce back to being the Liiga leading scorer/that guy we saw in his first flashes in San Jose a couple years ago. These aren't ideal linemates to do it, though I think Gregor could be a 15 goal guy, but the Sharks don't really have actual ideal linemates for that.)
Marleau - Handemark - Nieto (Marleau doesn't have his hands anymore and Nieto never really did at all, but at least give Handemark as much skating/hustle as he can get to ease him into the league.
scratches: Kellman (for versatility), whichever of Gambrell or Sorensen doesn't get traded (the former can probably fetch a better return, the latter offers more cap relief. Though neither would garner that much interest)
This leaves True, Blichfeld and Bergmann to log good minutes for the Barracuda. It also leaves the Barracuda with like 16-17 forwards who could/should fight for ice time and probably necessitates some loans or trades to sort things out (Bergmann, Blichfeld, True, Chmelevski, Chekhovich, Gabriel, Gallant, Garreffa, Halbgewachs, Leonard, Letunov, McGrew, S. Pasichnuk, Topping, Viel, Weinger, Wiederer, and Yurtaykin are all under Shark/Cuda contract at forward. Chekhovich is expected to spend the whole year in Russia even if the AHL starts up again, and Garreffa, Pasichnuk, Weinger, Wiederer, and Topping are all non-NHL contracts and likely have lower priority in getting ice time. So...
Leonard - True - Blichfeld
Halbgewachs - Chmelevski - McGrew
Bergmann - Letunov - Gabriel
Viel - Gallant - Garreffa
spares: Pasichnuk, Topping
Chekhovich remains in Russia, Yurtaykin and Wiederer are loaned out, Weinger to the ECHL.
total guesses on my part though.
In terms of prosepcts getting ice time it's probably dicey for most of them. Few are ready for top 6 roles and that's where the Sharks have openings. Blichfeld, Leonard, and maybe Chmelevski could push for a gig there if they get off to a strong start, but it's not a guarantee. I feel like they probably have too many bottom 6 veterans to want to displace them to play a youngster at a role they're not ideally suited for (except chemelvski, who could take the 3C role if he shows himself ready.)