Headlight switch has a rheostat on it to adjust the instrument light brightness. Possibly dirty contact or spring on the rheostat . Might need a new headlight switch.
Possibly timing also. Next time if it happens, to confirm it's timing, disconnect the power wire to the coil, or the wire from coil to distributor and see if engine turns over normally. If so, timing is too far advanced and needs to be retarded a few degrees for initial timing.
I've heard that you need to do that when you replace rod bolts with ARP hardware, to cut and hone the rod caps, but not with mains when you add studs because of the metal thickness.
The egr valve diagram is bad, not holding vacuum when you apply it. The valve closes off the port between the intake and exhaust. If the valve is stuck open, it can cause an intake vacuum leak.
Pull a valve cover and look for valve stem seals. Either there are none, umbrella seals of the seals aren't on the guides but rode up the stems.
Shop probably knurled the guides, which is only a temporary, cheap fix. Old school cheap way.
Why is the arm of the brake pedal and the e-brake rusty??
Attention to detail? Not in my opinion.
Nice build, but not my preference.
I think the builder saw a cash opportunity and convinced her to dump a pile into it..
Whoever made the video is amateur and the company owner constantly...