Harmonic balancer comes off

I think the dent you are referring to is the counterbalance system.
The 5 little bolts may or may not be correct. The 6th one with the screwdriver slot should not be there, nor should the spiky washers.There should be 6 hexhead bolts with spring washers or Belvilles. The factory bolts had special captive washers. It's not real critical, until the pully comes off at 6000 rpm.
The 1/20 side wiggle, if I understand it correctly, says you have a junk part there, or maybe two.The damper should absolutely not slide onto the crank and then wiggle. Time to measure both.
Here's the thing; this interface is pretty important to the life of the engine, and so it makes me wonder where else corners were cut with this engine. I'm not trying to scare you, but this stuff IS scary.