About Marner: I think you have it backwards. The more time that goes by the lesser and lesser likely he is to get offer sheeted. Reason for that is how the CBA was structured to factor in signings later into the season.
This does not mean a player makes more money just because he signs later into the season but it does mean said player's cap hit does go up because the numbers are pro-rated.
The other thing is Marner has to sign an offer sheet but so far he has declined offer sheets.

I suppose he can change his mind but teams wanting him will need to keep that pro-rated cap hit in mind. It will be unforgiving.

Fair point. I just feel that since he has not been happy with the contracts the leafs are offering he could convince a different team to OS him with a contract he wants. And even though he wants to stay with the leafs he could pressure them by signing an OS

I sure would like to see an offer sheet because really, it could be just a phoney smokescreen that Marner's side is using. Sure there are a few....and very few teams that could afford Marner this season, but then these teams have their own RFAs to sign next year and then they get in cap trouble with an inflated Marner contract.
You're right Marner might be unhappy with the Leafs offers so far, but he must be unhappy with any offers the other 30 teams are offering.....or else he would have signed an offer sheet. All 31 teams aren't in the business of making Marner monetary happy.
What's all this love for Shattenkirk? Yes, he might be cheaper than Ceci if he ever came to the Leafs, but no reason in 2019 to think he is any better. I like your optimism with the return of Dermot and Hyman, but then there is good chance that other players are on LTIR also. Either way it looks like a real thin defence this season.