Re: I know this is a big topic on here Iíve been going over it for the last few dats
The plants can handle drier air if the substrate stays moist for their roots - you don't need to dry out the lower layers of your substrate. Without the Cholla I'd guess you won't see the mold bloom as badly again. You can likely go ahead and close the viv and re-start misting.
This being your first viv there are lots of lessons to learn. But if you are patient and diligent it's pretty easy to keep happy and healthy frogs. They aren't nearly as concerned about the aesthetics of their enclosures as we are :-)