Wheel size is perfect and If I remember right the pine pellet cat litter is fine.
That cage is wayyyy to small
76×42cm only gives 3,192cm floor space which is by far too small.
I believe the absolute minimum is 100x51cm which gives 5,100cm floor space although bigger is better. And this is actually debated about even being too small for them.
115x49cm gives 5,635cm floor space which is okay but some people still think its too small.
115x61cm gives 7,015cm floor space which is even better for them and is more ideal space for them.