Can a phone be powered up without all components plugged in?

I’m trying to pin-point a suspected short-circuit that is causing heat to be focused on the main speaker during standby. There are several unrelated issues with the phone: touch ID not working, mute switch not working, and non-OEM battery. I guess any of these, or indeed the speaker itself might be the source of the issue.

My plan is to open up the phone and eliminate each of the suspect components one at a time by removing one of the connectors and re-booting whilst suspect component remains disconnected to check for reoccurrence of the short.

Will this work (i.e. will the phone start-up without all components being plugged in) and is it safe for the phone for me to do so?

Thanks.