Ack, hit backspace and lost everything I wrote up. Anyway, here's a shorter version.
Mute City: I ban this against SDM (MN's best Peach), because the lack of a grabbable ledge = dead ganon or living Ganon with a lot of damage taken during edge-guarding. The weakest of hits can send ganon off-stage out of double-jump reach and then Peach can abuse Ganon's up-b all stock. Ganon really doesn't have a way to make up for this.
FoD: I could see this being a good Ganon stage because the top platform allows for great platform camping. Peach really can't do much to a platform camping since if she pulls a turnip while below you (and you can avoid them by jumping/shielding), you know she is probably going to throw a turnip next, and jumping up to dislodge you means she is commiting to attacking you and then you can either stomp her through the platform or run away and kick her or something and then jump back to your perch. The floating platforms are problematic but that can be fixed by just spending as little time as possible using them.
Finally, how do I fight peach on stages like FD without platforms? She controls space too well with turnips and she has high priority. I feel like I either have to catch turnips (I have reaction speed) or keep close to her the entire match so we can fight at melee range and I can usually do okay then. Any other tips?
EDIT: Also, if my FoD paragraph didn't make it clear, I think platform camping in general is a viable strategy against Peach, at least in short spurts and I have had some success employing it. Just throwing that out there.