I'd probably offer Xander and Raffy similar deals - 8/240-250, with 2 option years @25 per that vest based on PAs in year 8 (and 9) and a$10m buyout. So guaranteed 250, max is 10/290-300. Xander would be older, in the later years of the deal but I'm more confident he'll still be in decent shape and will retain at least his bat-to-ball skills. Each will probably have to move positions in 3-4 years, but in both cases they're being paid for their batting skills rather than defense. X does get the SS premium in the short term, and both need to be recognized as franchise cornerstones.
My next move would be to try to get Trea Turner to play CF or RF and bat leadoff. He played some OF back in his days with the Nats and was pretty decent. He might be open to it Or at least as open as he might be to team that want him to play 2B). It's worth a shot - we need to upgrade the OF, and getting a leadoff hitter would also help.
That would cover it from the offensive side, I think. I'd consider bringing JD back on a short-term deal (1 or 2 years) for a lot less money ($10m per), but he'll probably get more elsewhere.
Spend the rest of the money on pitching, especially on at least one major addition to the bullpen.