I think the current locks should be the DRY line, Archibald on the fourth line, and Turris as 3c.
Puljujarvi or Kassian can be McDavid's right winger depending on who is playing better, but to start it will likely be Zack, given his previous experience on Connor's line.
On the left side, there's a bit more uncertainty with no clear top 6 LW after RNH. If Holland makes no more additions, it'll either have to be Ennis or Neal. I don't think Neal has great chemistry with Connor and he's got heavy boots as well, so we'd likely see him on the third line, leaving Ennis on McDavid's left.
Then, we have Chiasson, Khaira, Haas and Nygard battling it out for the final two spots on the fourth line. Khaira is the only one of the group that kills penalties, and he's better at face-offs than Haas, so he's probably our defacto 4c for now. Depending on who is playing well, I could see any of the remaining 3 draw in for the final spot, but let's assume Tippett goes with the veteran for now. I'm still not ruling out a forward trade though.
For right now, we then have the following up-front:
Ennis - McDavid - Kassian
RNH - Draisaitl - Yamamoto
Neal - Turris - Puljujarvi
Chiasson - Khaira - Archibald
On defense, Nurse & Bear are the obvious pairing. Barrie probably needs a more defensive-minded partner if he's going to be joining the rush or trailing the play as the fourth man. Jones is still a rookie, so I think they'll likely start Russell with Barrie, but that is subject to change depending on how Caleb plays. Larsson and Jones have chemistry from last season as well.
This gives us:
Nurse - Bear
Jones - Larsson
Russell - Barrie
The bottom two pairs likely play equal time, with the "third" pairing above playing more on special teams (Barrie pp, Russell pk), and the "second" pairing playing more at 5v5. I expect Nurse & Bear to log the toughest minutes until Klefbom is (hopefully) back.
Finally, in net Tippett will likely try and ride whoever is hot again, so unless Koskinen really grabs the reins this season, I can see them splitting time pretty evenly.
Koskinen / Smith