Oversized thrust bearing

I am not aware of anything like that.

As for another crank.... you DON'T have to re-do the whole re-balance job. The bobweights of all of the piston/rod assembles should have been matched in the original process, and there is absolutely no reason to do that part over with another crankshaft. You just take the bobweight that was used to balance 1st crank, and balance the 2nd crank to that same bobweight.

Talk to your shop that did the balance work and see if they kept the bobweight data. That would be easiest. If not, then they should be able to take any of your piston/rod assemblies apart and re-measure the bobweight and use that to balance the 2nd crank.

You'll have to take them the damper, and flywheel or TC+flexplate, that you took them before, if those were used in the balance process.