1. Yes, it's better to remove the bezel I think.
2. Yes! Remove the pearl first, then you can pull the insert with a toothpick out.
3. A gen Rolex insert can be used, but you have to grind the inlay on sandpaper, on the side and the underside. It's a very long act, I can tell you!
I also have a aftermarket inlay with gen pearl, and it click's it in the bezel without modifications, but the inlay is unter tension! It can click out everytime...
For the CG's I used a "Dremel", but you must be very careful!