1. Only the norton will need the 1/8 lapping. All the other is just till flat.

2. The stones are good but wood get a dmt d8c for lapping as those lapping stones aren't great and you need to lap it to start out with.

3. The discolouration could be swarf. Clean the stone under running water using your hand like a lap. If it comes out good if not lap it a little but really shoudln't cause an issue

Honing can take a bit to learn. Watch the vids by Gssixgun and Lynn Abrams on youtube. Good luck