What rule are you referring to? Do you have a link or something? Why would they have lost a first round pick if they signed a UFA that was unprotected, after their exclusive negotiating period ended? They signed Schwartz as UFA, who was unprotected, but picked Dunn. They signed Johansson, who was also unprotected, but picked Soucy. Heck, from the very same Panthers they signed an unprotected Wennberg after waiting until he was UFA, but picked Driedger. Why could they not have done the same thing with Driedger, and picked another cost controlled asset?
The league also didn't do a thing about deals like the Ovechkin/Capitals arrangement - I can't imagine they could do anything about a team signing an unprotected UFA after picking another player from the same team (which they didn't do, as illustrated above).
And is the risk really that high? If Driedger didn't want to go to Seattle he wouldn't have signed the deal during their exclusive negotiating period - he would have declined the offer and gone to UFA.
Lastly, I think you are mistaken about how much effort the Sabres are going to to spend their cap and ice a competitive lineup this year. All signs seem to be pointing to them committing to a rebuild. I don't see how they serve as a cautionary tale about the risk of signing a UFA that demonstrably wants to sign with your team for the terms you are offering. Who do you think Buffalo had a similarly reasonable interest from, that slipped through their fingers?
And regarding #2 - why was the lost 2nd round pick worth it? Was Vanacek really that critical a piece of their proposed roster, so much so that another player, a 2nd round pick, and an alternative goaltender in the market wouldn't have sufficed?
I don't know. Ron Francis clearly hasn't capitalized on at least a handful of opportunities so far.
Maybe I am misinterpreting your implication of "deal in the drawer", but the league has shown time and time again to drop the hammer on any team taking liberties with loopholes. The Expansion draft rules are clear, "if a team signs a UFA, that will count as the expansion player drafted from that club". Setting up a contract during the window, and holding off on submitting it till the UFA period to double dip from a team in the draft would be a clear violation of the spirit of the expansion rules, and the NHL ABSOLUTELY penalizes teams committing rule infractions with extreme prejudice (New Jersey, St. Louis, Arizona. etc)
And yes, the security with the Vanecek pick was totally worth the late 2nd round pick that they did not get. Judging by your repeated misspelling of his name, I have a feeling you are not very familiar with the player.
There was a huge uncertainty about which, if any free agents might want to sign with an expansion team, and while there were several goalies available, the proven starters without serious question marks or injury histories were slim pickings.
The odds in Vegas(casinos, not golden knights) Grubauer would sign with Seattle were so low, that if you bet on it, you'd be a rich man now - so pretending that it transpiring and not being part of the plan in Seattle is some sort of mark against Francis is ludicrous.
Having Driedger and Vanecek as a plan in net was very solid. Francis upgraded and picked up a second in the process. Nothing wrong with what transpired. It is all fine to measure opportunity costs in a vacuum with 20-20 hindsight, but to pretend that comparing those to real-time decisions in the real world is realistic is completely disingenuous.
The belief that all the other GMs weren't playing poker the entire expansion draft and instead showing their hands to Francis so he could get the best deal from each team is totally unrealistic. Your simplistic generalization of "the established trade value of the piece(player)" is silly. I would bet that if Chevy tried to trade Dillon right now for two 2nds, there would be zero takers. established trade value is not a thing other than what one GM was willing to finally give up for a player. It does not mean the player is worth that value around the league.