Well Fulmer is certainly the kind of player the Phillies would be interested in though I'm not sure they could pay the freight right now. Controllable until 2023. I would think one of Kingery/Crawford or Williams/Altherr would have to be in play there.
Moustakas or Beltre both make sense as cheaper rentals, and the Phillies could definitely use Moustakas's power even if Beltre's profile seems more Klentak-like. Moustakas could also be re-signed, of course, depending how they decided to go next year. Don't think the FA market for him is going to be that much better than it was this year. If they decide they like him and want him there'd be a deal to make. Boras is their pal now!
I'm not gonna lose any sleep if they don't get Machado this year. If that's the call they make I trust it's because the price is too high, and because they still feel good about their history and $$$ to get him in the off-season. Sure, whoever trades him might keep him but that's what everyone thought about the Dodgers and Yu too. Those teams are not necessarily in the same position to offer the richest contract ever (barring if Harper beats it).
The other reason to prefer Moustakas or Beltre is you can make the deal now if you want. I don't really believe the Orioles will be able to pull the trigger on Machado early.