Really like your takes on the lines, not too far off of what I've been penciling in but Marner is as much a sure thing to make the team as any player out there.
Not criticizing exactly you directly here really but Marner is the reigning first team NHL all star at right wing. He has more primary assists in the NHL over the last 3 years than anyone not named McDavid. He's also a high motor defensive stud that finished 10th in Selke voting and has underlying numbers pointing to him being one of the best PKers in the NHL. Only having 4 points in 7 games against the best goalie in last years playoffs doesn't seem a strong reason to be cutting him from the team IMO (This seems to be the argument most folks are using along with talking about $ for some reason) and his underlying playoff possession/shot/scoring differentials over the last two playoffs are the best of any right winger in the league.
The only question with Marner is if he will be used on the top line with McDavid/Mack or if he will be reunited with Point from the world juniors line.
With the best line of any team from 2016 still intact and productive (Marchand - Crosby - Bergeron), I think the lines will probably go more like this:
MacKinnon - McDavid - Marner
Marchand - Crosby - Bergeron
Barzal - Point - Stone
Stamkos - O'Reilly - Tavares
(Huberdeau, Couturier )
Insane scoring lines that include 5 of the top ten Selke vote finalists this year make this a nightmare for any team. I'm not sure how any team could contain the pure level of production and creativity that top line has. The only issue there would be chemistry so lets see how it pans out. The second line is a lock on literally everyone's list The third line could be many others teams go to first lines and will feast on favorable matchups. I would especially like to see Barzal unshackled from a more rigid system on the Isle to see what he can do. I think Marner/Stone can be swapped freely here to balance chemistry just right. I was going to leave certain players off if it were big ice but the highly effective Stamkos/Tavares combo from 2016 comes back with O'Reilly replacing Getzlaf down the middle, albeit in a reduced role compared with being a stud 2nd line back then. They will grind other teams depth lines into the ground and can really put the puck in the net too.
Theodore - Pietrangelo
Chabot - Makar
Rielly - Ekblad
(Hamilton)
Not too far off of many folks list but I really think Chabot needs a look in at a major role this year as he has been an absolute beast on a putrid team since he entered the league and stood out whenever he put on a team Canada jersey. I'm fine with Nurse being granted a role here like you but I'm not completely sold of him quite yet.
Price
Fleury
(Kuemper)
I think the fact Price was the best goalie from the playoffs completely solves the problem of who starts in net TBH. Price is the reigning BoB gold medal goalie so he gets the net as he looks in good form. How the season goes can change that a bit but I dont see him not starting. I share your concern about the future though after the implosion of Carter Hart last season.