That's not getting Tanev and Hanifin not even without retention. If you want both with 50% retention start with the 2024 1st, Minten and Knies and add to that (not just pure cap dumps either).

May as well throw in the rest of our prospects as well and make sure the Leafs become the oldest team in the league

Hanifin should get a fair price but he's a rental so a team that has a chance at resigning him will pay more than the Leafs would. Tanev won't get what you want though. I wouldn't even trade for him. He's purely a rental and is already declining.

Hanifin and Tanev traded separately at 50% retained, Get a far better offer than this. No reason for Calgary to accept that offer.