Both side swat switches are safety devices to prevent retracting the landing gear on the ground. However, don't rely on them since even a moderate taxi speed or a bump in the runway can close/open? the switches and let you retract the landing gear while still on the ground. Just pretend they are not there and retract/lower the landing gear at a sensible altitude.
I don't know about BE76 and unfeathering accumulators, but on my airplane they were used to help unfeather the prop after an intentional engine shutdown by moving the prop out of feathering range so it could start to windmill by itself. They look like air pressure containers in the engine compartiment and should be refilled with air pressure during inspections. Your maintenance people should know if they are installed or not.