The value is more than fair, but Tampa probably doesn't move Cernak unless they have a deal elsewhere set where they trade 11oa+something for another top 4 dman. Jokiharju also needs a new deal, and while I'm sure it wouldn't be a large number, Tampa will be needing all the space they can get. Since Tampa already has Raddysh and Crozier on the right for 5/6 types, not sure where Jokiharju fits tbh. He could be 3RD I suppose, but in the end I think Tampa would just prefer to have Hedman, Serg, Cernak and Byram as the top 4, with Raddysh, Lilleberg and Crozier as part of it.
If Tampa knew they could move 11oa as part of a deal to acquire someone in the range of Rasmus Anderson(if even available) or another top 4 guy, or alternatively, if Brisebois felt confident he could sign a ufa dman for no more than Cernak's hit, then maybe.
Tampa would definitely accept the Jeannot trade, but it is an overpay on Buffalo's part given the issues with Jeannot lately.