Yes, an AC 30 would be perfect for a 10.
Generally, UGF's won't clean gravel, unless you have a reverse flow unit(Forces water up through the gravel), these typically require one or more powerheads.
Third question, no, AC does not have biowheels. They have a basket, which contains three different types of media which can be custom selected, three at a time. Choices of media include sponges, carbon, ammonia removing media, combination ammonia/carbon, phosphate absorbing, ceramic biomedia, peat, etc. When new, they come with one sponge, one carbon and one ammonia packet.
They are very flexible; in one of mine I have 2 sponges, ceramic blocks, filter floss(Also called poly wool), and phosphate absorber(which I stick in the side near the impeller).