Trading Vaughn for Manaea makes this offseason ever weirder. That's an all-in move, and definitely does not fit with the rest of the offseason.
If I were the Sox I'd probably try to build something around Jose Rodriguez + Kelley/Thompson/Dalquist. Anything beyond that isn't worth it for a rental for me. I'm not moving Kath, Montgomery, Vera unless we are talking legit ace.