James, I can only go from what I do, but in answer to your questions:
1. I use either a razor saw, or a small razor saw blade, about an inch long, in a scalpel handle.
2.Use superglue, or possibly epoxy.
3.I usually just wash them thoroughly in detergent and then paint, but I know several manufacturers, Gunze for sure, produce a dedicated resin primer.
Hope this helps.
Karl