My thoughts on the vets:
Backlund is the captain, so unless he asks for a trade, I would keep him.
Coleman is my next 'best vet' on the team. He is the only other person that I would really want as captain if Backlund left. I would only entertain trading him for an overpayment, or unless he asks to be moved.
Weegar is another solid vet. However, he isn't perfect in terms of leadership, as I do remember after the St. Louis game he said: "They broke us" comment. Overall, a solid vet though that plays well game in and game out.
Kadri did great work with the kids this past season (credit to him, as I thought he would roll over and die like he did the previous season). However, that's 7 million on the cap for far too long, especially when the Flames have Huberdeau's deal for a year longer. If you can move him, do it.
Andersson - I have zero issues with keep Andersson around, but that's a very attractive contract similar to Hamonic's at the time (and Andersson is a better player!). Flames could really get a ransom here, otherwise I am fine with keeping him.
Lomberg was just brought in and will be a great guy to have around this team.
Hanley is a journeyman - I expect him to be a 7th D (and I think the Flames carry 8 this year), if he is a good leader, otherwise he is likely waived and sent to the AHL.
You can always find a good vet that is trying to hand on for another season, or a shot at the cup. If he doesn't find a spot on a team, he can then circle back mid-offseason and try to at least find a spot that will allow him to showcase himself for the deadline.
Here is an up-to-date (fairly accurate) list of UFAs still available. Some of these guys will bring a lot of leadership to fill in a hole left if Calgary trades away a vet or two if given good enough offers.
https://www.spotrac.com/nhl/free-agents/_/year/2024
Someone like Okposo stands out to me. Maybe he is retiring, or maybe he wants another kick at the can? As other people have said, maybe Cousins? Maybe Shattenkirk for a vet presence? Giordano is around if you want a good vet as your 7th. Point is, there are options.
I am of the opinion that culture has a lot to do with winning, and bringing these kids up in the proper culture does help. This is why Conroy doesn't want to do a scorched-earth rebuild, and I agree with him completely. However, if I am him, nobody is really off-limits, but if I do trade a vet, I would try and sign a vet to replace that leadership.