If the trade happened, it would open up alot of possibilities for Nashville. Callahan's buyout would put them back to the caphit they had prior to the trade. Having Palat would allow them to trade Smith or Granlund which would open another 4.25-5.75M which would then open up enough room for Duchene which would then make one of Turris or Bonino unnecessary. Move Bonino and let sissons replace him on the 4th line. Foote wouldn't be needed to play this season. He would just be someone to come up as Ellis ages.
From Tampa's spot, if they miss out on EK then Subban would be a pretty good Silver Medal. It keeps them from having the dead capspace of Callahan's buyout. With Subban, Hedman, McDonagh, Rutta, and Sergachev a plug will be able to fill in as the 6th dman. Tampa may need the cheap talent more though. But if that's the case i don't know why they were going after EK to begin with since that doesn't help their situation anyways.