1) "I turned the key to the on position (didn't try to crank it at this point). My buddy could hear buzzing coming from the main pump under the car but heard nothing putting up his ear to the open gas tank fill hole."
• Then we know the pump runs when it gets voltage. Tank pump is less certain. They can be hard to hear depending on ambient noise level. Try removing fuse 4 and jumpering from 6L to 4R. That should put power only to Tank pump, which is really a moot point right now. IMO.

2) "I tried to crank the engine over with it jumpered-but it wouldn't start."
• How long did you crank? 3 seconds? 5? 10? A wild guess is that you may have stopped cranking just as the fuel rail got filled (which could take longer than normal if Tank pump was inop).

3) "When I disconnected the jumper wire I tried again to start it and it did start right up and ran for about 5 seconds,"
• Still flogging the wild guess—it started on the fuel (and residual pressure) from the failed attempt -- and then ran "dry".

4) "again I jumpered it and listened to both areas with same outcome, buzzing from main pump, nothing from in tank."
• See my question at 2, above. Again, the fuel rail was repressurized but maybe you stopped cranking too soon?

5) "Again,I tried to start with jumper disconnected and it started and again only ran 5 seconds."
• See my comment #3, the wild guess.
To better test the Tank pump, remove fuse 4 and jumper from 6Left to 4Right putting power only to the Tank pump, as I mentioned above. If your jumper has clips, you can go back and listen yourself.
But the fact that it ran for a few seconds (twice) with NO pumps running makes me rule out the Tank pump as being the main problem at this point.

Jumper again (6L=>4L) with fuse 4 in place and try cranking a bit longer, say 5 or 6 seconds. Maybe I'm missing something, but that's all I have right now. Will you be able to take the battery someplace for a charge, if it comes to that?

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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.