The difference between the L5 and L14 is that the L5 is 120V while the L14 is 120/240V.
The receptacles are not mutually exclusive, you can use them all at the same time, as long as you don't overload the generator.
If using the 120V GFCI receptacles worked for you, then you have nothing to worry about. As long as you weren't tripping the breakers, keep doing what you were doing.
If the breakers were tripping, then you have the option to rig up (or purchase) some type of system that you connect to the twistlock receptacle (which has 30A available, or 60A at 120V for the L14-30R) and have multiple receptacles, or you can just hookup a transfer switch or interlock kit to connect to your house wiring.