Electric Relay Advice

- electric trunk release............no, pretty low current
- aftermarket stereo system........likely not, depending on how it's wired. Most stereos are "hot" and the switches in the stereo take care of all that
- push button start.....either use your stock start relay, or replace it with a Bosch style relay
- aftermarket A/C....No it should have it's own controls
- back up camera...No, low current

Main stuff:

Headlights, a relay for high and a relay for low beams. The light switch goes to the dimmer switch. The dimmer switch keys on one or the other, hi or lo beam relay

Fuel pump, EFI if used

Use at least one relay, triggered by the key "run" circuit, to power the underhood loads, ignition, VR/ alternator field and whatever else is no the "run" circuit

You might want to do the same for the accessory feed.........use the key switch to trigger a heavy relay, and the relay will power "on" the accessory buss.