On a typical RV the frig can operate on either 120 volt (household power) or 12 volt (battery) with propane. The slide motors use 12 volt. When hooked up to household power, a converter, converts the 120 volt power to 12 volts to run the lights, other 12 volt loads and charge the battery.
So, the answer to both questions is yes, you can use house current to run them... The frig will only need approx. 500 watts - so any household receptacle should supply that - you will need adapters to get from the 50 amp cord to a receptacle plug. If you have a good battery the slide will operate with or without house current. The converter will replenish the battery within a few minutes using 2 - 500 watts to recharge the battery. If there is no battery the converter may not supply enough current at 12 volts to operate the slide motor.
Just don't try to run the AC while connected to a typical 15 amp receptacle... And use the shortest extension cord possible - 10 or 12 gauge.