[cypher]

A smaller cage may be ok for a while as he's young & getting used to you, changing the cage should be fine though, if you make a bin cage you could just let him play in it a few times before moving him in.
Don't clean his cage for a couple of weeks at least (apart from spot cleaning pee) before the move then move all the substrate into the new cage, you will probably need more in a larger cage so put the old substrate on top of the new, that way it will have his scent on it, try to keep everything as similar to his old cage as possible & he should be fine, it may take him a little while to settle again but that's normal so don't worry.

I would. try taking him out for taming, especially with a small cage a hand in the cage may be too much of an invasion. Once he's used to you being around & talking to him try to get him to climb into something you can use to safely carry him to a playpen, play bin or whatever you have for some out of cage taming time.

The best silent wheel is probably the silent runner (not silent spinner!) there is a thread here on wheels that you might want to look at.
Guide to suitable hamster Wheels