If you are going to run all those electric heaters at the same time, be aware of what other things you run like hair dryers, coffee pots, microwave, elec fry pans etc as otherwise you will be running outside to fix the tripped breaker often. Also may trip the trailers breaker on the electric panel inside. \
I'm not sure how many things you can run at once in a 50amp rig but in my 30amp it is only 3 big items like microwave, coffee pot, and electic heater. In fact, I added a new 110 inlet/outlet in my slide out to be able to use an extension cord from the campground pedestal for our electric heater.
Barney