Please Help identifying underhood components

I'm pretty sure "A" is not the VR but rather part of the smog system.

The benefits to headlights relay will unload the light and dimmer switches. The bulkhead connector might not be much of an issue, but might need repair. The big benefit using relays is the wiring "may" be quite small. I don't know if 76 upsized the lighting wiring or not. Also if you put heavier headlamps in, like halogens or etc, the relays are almost a necessity

the 76 does not have "'the usual" bulkhead connector issue because the ammeter is not a "full current" type, but rather external shunt

If you are going to keep the car you really should get you a repop or original shop manual, either paper or "on cd" You cannot download them that late.