re: "...While viewing timing with the timing light the mark on crankshaft v-belt pilley will appear in a different location every time the timing light flashes, is this acceptable?..."

Unfortunately, the inner and outer ring of the front pulley (a vibration dampener) has separated, and they're spinning separately. New, they're bonded together so the timing marks on the outer ring stay synchronized to the crankshaft. In your case, that outer ring is just slipping around (and also causing your accessory belts to not spin as fast as they should). It should be replaced -- and since you're already doing the hardest part of a timing belt change by replacing the pulley, you might as well also change your timing belt and tensioner now.

And on the fuse 4 power, use a test light to pinpoint where the power is missing. About the only reason for the right side of fuse 4 to lose power given the main pump under the seat is running, is a corroded fuse. Probe either side of the holder with your test lamp. If the left side is unpowered, I would look behind the fuse panel for a loose faston.

In The Tank

--
Art Benstein near Baltimore

Be nice to your kids. They will choose your nursing home one day.

It sounds like the harmonic balancer is slipping and should be replaced.
Information given to you based on the location of that mark in relation to timing is of no value once the balancer has slipped,Once this slipping problem worsens it will directly effect all belt driven accessories(could cause overheating and charging system failure).
I do not think this has anything to do with the fuel pump voltage situation.