GameCube homebrew questions

I'm about to get a Cube with a XenoGC, and I wanted to ask some questions:

1. Is there a SNES emulator that will run on the XenoGC at fullspeed with high compatibility, and the ability to save?

2. How do I burn .GCM files? Do I just write them to disk through a regular PC dvd-writer?
3. How do I read gamecube disks? Do I just read them with a regular PC dvd-writer? Because mine doesn't show them.

4. Is there a good N64 emulator for the Cube? The games I'd need to play include Harvest Moon 64, Sin & Punishment, Yoshi's Story and Majora's Mask.

Thank you sincerely for any responses.