When temporarily blocking off a light switch fixture, should I separate and cap the white wires individually?

== wires must be capped and black taped for safety when not in use === if you cap those wires...... together you will complete that circuit and that will cause the breaker to trip .... in this case the code has nothing to do with your planned renovation and change out of the bathroom vent, light, heater == please do not settle for a cheap unit when you go to replace [[ they do not last ]] get the guy on the electric lights isle to explain how to rewire to the new unit --- take your pen & paper to make some good notes and remember what he says ...all wires should be capped separately and you should mark which wire goes to what switch as I assume that each function of that old unit had its' own switch ...

You need to figure out which is the hot wire from the breaker (one of the blacks). The neutral for the circuit is the white wire in the same cable as the black above. The other black an white just go to the switch. One of the wires will connect to the black hot. The other wire coming back from the switch will be the "Hot" when the switch is on. Connect it to the lamb black wire. The lamp white wire goes to the circuit neutral with the incoming hot black from the circuit panel. Draw yourself a diagram if you need to. Tie all the grounds togheter and to the box if it is metal.

The white wires are neutral wires. They should be left together but wire-nutted (capped off). The same is true for the black (hot) wires. They need to be wire-nutted individually. Do not twist them together, for that would be the same as having the switch on.

The white wires are fine together, but you should wrap electrical tape around the cap and the wires so there is not chance the cap could work loose.

No, the whites must be all connected or you lose power to anything farther down the circuit, same for the blacks (if there are more than the one going to the fixture).

1

Switched circuits go somewhere. It is Code that every room have either a ceiling light or outlet that is switched. If you remove the switch, you may be violating code.