The feel of the rep straps and clasps can often be improved with a cape cod cloth and a bit of filing. A bit of oil may also help to make it feel smoother, I am sure there is a tutorial on this somewhere.
You can get stick on dial feet that you can place anywhere on the dial, or use dial dots to glue to the movement. You probably need some kind of date wheel overlay for that to line up.
Try gluing the SEL back together with some 2 part epoxy, even if it does not hold, it would be held in place by the spring bar so you wouldn't lose anything.
If you are able to remove the caseback it would help to diagnose the problem.
Crown should push back into place quite easily, and will make a clicking noise when attached correctly.
Does anyone have any drawings of gen cases? Or something similar that shows the dimensions of the genuine cases? I am wondering about installing an after market tropic to a rep datejust case, and wonder if the dimensions of this part of the case are the same. I suppose if someone has the dimensions of the genuine crystals that would also be helpful. Thanks.