Everyone seems to worry when they start off. Your seems more extremes then normal. If you say you got him yesterday right now you need to let him be. He shouldn't be bothered for the first week. If he is set up properly then you don't need to go ino his tank. Even changing his water suing this time isn't a huge issue and can easily be done without disturbing him at all if need be.

You are getting too worked up over everything at once. Take it slow and step by step. Right now you shouldn't touch him so don't worry about handling him at the moment. Let him get through the adjusting period then worry about stuff like that.

Where do you live? Sometimes the humidity isn't as much as an issue as people make it out to be but that also has to do with what climate you love in.

Does his thermometer has a probe? That is what souls he over te UTH. Not the whole thermometer it's self. If it doesn't have a probe get one, get the tank setup properly. Right now get the tank they way it should be. Focus on the one issue. Once tht is done then let him be for a week. Then when that is done take a new issue and deal with that. There is a lot you are going to go through during this time. Take it step by step. Don't let it overwhelm you. THat is what you are doing right now which is causing all your stress. Breath. Relax. It will be ok.

Also ou mentioned you needed to fluff up his aspen. Why are you doin that? Unless he goes to the bathroom you shouldn't need to do anything to the substrate.