A naval base isn’t needed to load transports. A transport can take 2 units from 2 different territories as long as the territory is adjacent to the transport’s sea zone. It can also take 1 unit, move into another sea zone, and load another unit from an adjacent territory.
And yes, you can use Eastern USA’s Naval base to move the transports to offload in Morocco. Naval Bases serve all friendly ships in sea zones adjacent to the territory that the Naval base is on.