1)
$03A8EE has the sprite number that peach spawns.
$03A8E9 has the sprite state which you can set to 00 to not spawn a sprite at all.
Dunno about the movement pattern but around $03AB17 are bowser related stuff
2) Thomas made one, not sure if he released it to the section but
he posted it on the forums.
There's also
this one but the comments say it doesn't work and I don't think it displays anything on the OW
3) Introduction is probably best to post in the
full hack releases section. Submission Rules/Standards for anything can will be listed when you press Submit File.