She can have room but ball pythons are not from a tropical environment and should therefore never be in the same habitat as geckos and frogs.
Fact is, your snake is in an incorrect environment and I would not be surprised if she develops an RI or scale rot because of the improper conditions she's being kept in.
If your snake is getting mites, keep on newspaper or paper towels and treat the mites with Provent-A-Mite. The reason she's soaking is because she has mites and your setup isn't doing anything for that. It's also probably part of the reason she went off-feed.
Also you need a new vet. The one you have is completely inept in that he's only encouraging you to do what you're doing and harm all your pets.