exterior NEMA 14-50 AND dual GFCI
You're not allowed to supply NEMA 5-20R receptacles with a 50A circuit breaker.  That is dangerous!
I suggest an additional penetration for the new receptacles, which should be put on a 20A breaker(s).  You probably don't want to stuff additional wire into the conduit that already has the RV circuit going through it.
If you don't think you'll use both the RV receptacle AND the 20A receptacles at the same time, an alternative is to get a portable power distribution box with a 14-50P inlet plug.  These are available for rent at most equipment rental yards that rent generators, too.