There are lots of clues to this puzzel and trying to diagnose it over the internet takes a big imagination and good old experience.
Here is the latest clue directing the problem to the inner workings of the transmission. The way you bought the transmission from someone (a stranger) that delivered it to a show for you, saying it was overhauled, this is very, very suspect of all of your problems. Could have just been a junkyard rebuild quick job, just to turn the used transmission into money for the seller. Or maybe not even rebuilt at all, just cleaned up to sell.
Your Quote:
I found this one rebuilt and ready to go and able to be picked up at a local show to me..
Unfortunately people lie all the time when trying to sell you used parts that they want to turn into money (especially from a stranger). So much so that: Everyone is lying until they can be proven otherwise.
You were saying your friend looked at it before you installed it, but just installing new clutch discs does not constitute a good rebuild.