Logic behind both trades:

DeMelo for Fleury/2020 2nd: Fleury's been really good in Carolina, but he's been in a playing-time logjam for the entire season due to the acquisition of Edmundson in the Faulk deal. He's also being pushed from behind with the emergence of Jake Bean in Charlotte. Trading him to Ottawa for DeMelo opens up a slot for Jake Bean next season, and extending DeMelo for 4 years gives Carolina some insurance in case the Hamilton extension talks fail like Faulk's did this off-season.

Rodrigues for McGinn: Rodrigues is a pending RFA with arbitration rights, while McGinn has one year left. Buffalo, via this trade, gets a 1-year upgrade at the 4th line spot for one of the worst 4th lines in hockey (according to analytics). Carolina takes a swing on the right-handed Rodrigues, who's requested a trade due to lack of playing time.

Sens fan here.

Youre overpaying for DeMelo, but not by much.

We would accept this giving a 4th (instead of 6th) the other way or taking a 3rd coming back (instead of 2nd)

Is the DeMelo deal a sign and trade? Either way it is an overpayment. I feel we could get DeMelo as a rental for a 3rd and a 4th, and if we want to trade Fleury we could get a lot more value out of him in a separate deal, i.e. a 2nd+ good prospect or legit middle 6 forward 1-for-1. In a sign and trade I feel we could just do DeMelo for Fleury 1-for-1 or OTT adds a late pick. Fleury is younger, cheaper and under team control.