Solved, we have a winner!
Last night I installed the front row camshaft position sensor just received from Rock Auto (only took 3 days US to Canada), started the engine right away, revved just fine.
Cleared the P0345 Bank “A” codes, took the van for a spin around the block – she ran like a top, no more tranny thud when shifting.
No more codes re-appeared after the ride.
Hoping this is good news for everyone with the same problem!