As an owner of a 2016 Fleetwood Expedition 38K, I have two toilets in the bath and a half layout. Both are porcelain. Without additional input from the OP on their unit, I'll offer the following:
Mid toilet is a Dometic 311 Toilet. This is the low profile (15.25") variant of the 310 (20").
Rear toilet is a Thetford Bone Tecma Silence Plus Macerator Toilet. If ordered directly from Fleetwood, the charge is $1600.75 (plus shipping). This toilet does integrate into a flush control panel mounted on the cabinet next to the toilet, so you probably want to match a Thetford macerator toilet to be compatible with that.
Certainly, both toilets can be ordered from a number of third party suppliers.
You can look up your RV components directly on REV's Parts Store website:
https://parts.revgroup.com/storeGo to the link, click on the Motorhome Parts box at the bottom, Enter your VIN or Fleetwood Identification Number (FIN/UIN) in the search box, and select your vehicle. Search for the parts you are looking for.
If it is the macerator toilet that is broken, with that price, I would personally lean towards repairing it. I can only see replacement necessary if the porcelain was broken. All other components I would assume are replaceable if broken.