For what it's worth I personally think the USMC will (as it has done to date) fight tooth and nail for the F-35B. They already have some, as has been pointed out.
The USMC also has a strong political lobby, so it will undoubtedly have its case heard.
However, it is worth noting that for some reason the misconception exists that the USMC is a VSTOL force transitioning to STOVL F-35. This is somewhere between misleading and fundementally incorrect. I am prepared to stand corrected but I believe the USMC has circa 200 Hornets and circa 110 Harriers. It is taking delivery of 80 F35Cs I believe.
I know that the spectre of being left to fend for oneself in the Pacific is still writ large in the USMC psyche and have a feeling that the F-35B is probably born out of it. But so long as one model survives the USMC will have a FW capability. Not a bad position to be in really.