Personally I don't think moving Eddie and Hernandez is the right move, since I want to show the players the FO wants to win. So even if it's just a couple veteran rentals, it would show the FO plans on winning/making the moves when needed.
Marquez/Marte move wouldn't help the budget, but the FO wouldn't make the move if it effected the chance of extending who we have. Remember both guys have a fairly team friendly contract on paper for their playing level so it would be a move within the realm of possibility money wise.. Now when it comes to prospects being moved... I can see them not wanting to pay the prices that way, but sometimes you gotta gamble and I think they will do some type of gambling in 22/23 even after they extend guys. Dolan wants to win as much as we do it feels like, so I think he will okay a Miller trade again/EE signing in due time.