Often the ligs and tunica can take more weight than the softer tissues (blood vessels and nerves). Working up gradually gives these more delicate parts time to adapt.
That 10 lbs. will feel a lot heavier when the skin isn’t bearing the load. Maybe you’ll have more skin slack with the TPS hanger. Don’t be afraid to spend some time stretching only or mostly skin if necessary.
I don’t know about the soreness. Depends.
Fatigue builds over time. Don’t expect it on the first set of the first day. Sometimes I didn’t feel any fatigue until the 3rd or 4th set. Or sometimes no fatigue until only after several days in a row of hanging. That’s what I mean by it building. And at times I didn’t feel any real fatigue at all no matter what.
If you’ve only been hanging 2 sets I suggest adding sets before increasing weight.