Silverado Torque Conv. To Flexplate. Issue or not?

Good day,

I'm working on my 2000 silverado 4x4.

I've swapped to an iron block "LS2" and still have the 4l60e stock Trans. This setup has been together and running before, as-I'd, however due to the poor tempering of the cheap valve springs I got off Amazon, I dropped a valve. So motor was pulled apart, cylinder sleeved, new piston installed, new TSP Double Valve springs, and I'm off topic. My point is, this motor, crank, bellowing, torque converter, and flexolate setup all fit together... None of those parts have been changed...

Here's my actual questions/ issue.

When reinstalling the engine this time, I forgot to check the TC was seated all the way back into the Trans before putting the engine in, however I had an 1/8" gap between the flywheel and converter, plus the converter spins freely so I didn't think anything if it. Kept bolting things on and went to do the starter and realized I forgot the TC bolts.

So I started to install the TC bolts, and ad I tighten them up, instead of the TC moving forward to meet up with the flexplate, the flexplate actually flexed back to meet the TC. I've never seen that happen before. Every install I've ever done has the TC coming forward.

So I'm wondering is anyone has seen the center hub of a TC NOT slide into the center of the crank, and instead get hung up slightly out of alignment???

I've never had that happen, but until now, I've never had valve springs snap either..

So.

1) Does anyone know how common it is for the TC not to seat correctly to the crank, or is it even possible? (The TC bolts lined up fine with the holes in the flexplate, so it has to be pretty well aligned to center).

2) is there a way to check the cooling pump is working CORRECTLY once I get things running? I don't have a Trans temp gauge, but I'm wondering if I could pull a Trans line and see how much fluid is moving maybe?

3) Anybody else ever seen the TC "stay" and the flexplate "flex" to meet the TC?