For a week or two, what you have will be ok once you remove the moss. The problem with moss is that it can pose a risk for impaction if your chameleon accidentally eats it and it can become a bacterial mess in just a short time. Bare floor is best and most hygienic. The cholla wood is ok for now, but I suggest using regular tree branches that you can collect and wash/rinse when you set up the larger enclosure. Just avoid pine and other sappy trees. I see you have a linear uvb. Is it a T5 or T8? What is the strength of the uvb bulb? With the short enclosure, you won’t want to blast the baby with too much/too high uvb. For baby chameleons it’s best to raise all lights off of the screen as they are like little monkeys and will walk upside down on the top, putting them at risk for burns. I grabbed some little wire baskets from the dollar store to set my lights on for my young cham. The biggest challenge in putting a tiny chameleon in an adult sized enclosure is making sure they’ll be able to find their food. However/whatever method you’ll be using to feed, make sure it’s within clear sight from basking branch and try not to move it elsewhere. If you want, you can shorten the height of the full XL screen enclosure until your little one gets bigger. The floor can be moved up, making it shorter by placing something stable beneath it.