"push 'nuff water thru the ballcock to fill the toidy tank"

No blockages ANYWHERE? No inline taps turned off? [the old stupidity of the 'frig plug fell out of the wall' game!] You checked the toilet fills if connected to a 'mains' or local pressure supply with a much shorter feed length?


"air inlet to the supply tank"

The air has to get in to let the water out. Crack open the water fill hole cap. "don't think I can get the screw cap to tighten enough to put an air valve on the tank and compress the air above the water" SEEMS to negate that.


"pull the air from the hose"

Is there a 'siphon hill' anywhere for the water to get over, or it is visibly ONLY all downhill between the 2 points. If there is a slight uphill section near the bottom, it won't matter so much.


"100 foot garden hose" "garden hose hooks into the 1/2 PVC there is water there... Not a lot of pressure but water."

There is a considerable resistance in that length of hose, especially if it is a narrow one, but Pascal's Principle says that it should still flow, even if only VERY slowly, unless blocked. That may not be enough pressure/flow to open the ball cock, but gravity should drop it - is it stuck closed? You could try a wider hose.