Ottawa may want to trade its value pieces, but not sure the Flyers are the right trading partners in this situation. The Flyers have a ton of centers, either on the roster or as prospects. Trading for Duchene, and offering so much, doesn't address a need the Flyers have. I don't see paying that much and paying $6M for a 3rd line center.
I don't understand the Manning signing. He's more likely to be gone at the end of the season then to such a big raise from the team. They have AHL defensemen such as Morin, Myers, and Friedman that can fill his role.
For Carlson, the Flyers already have a top-2 d-pairing in Provorov and Gostisbehere. There's no need to spend so much for another top defensemen when some of that money could be used to shore up the winger depth or save a bit for Provy and other bigger contracts.