Oh, they're pretty close to you, then! Fluff-N-Stuff Farm in Alabama: https://www.facebook.com/fluffnstufffarm
Yes, the Chocolate gene is sexlinked recessive. First generation of a Mottled male to Chocolate female would produce all black offspring, all carrying mottled, and only the males...
Yes, you could. You'll be contending with lighter foot feathering, white skin, and oversized birds for a while, though. These Chocolate Cochin bantams were from a Chocolate Orpington outcross and you can see that they're not the best in terms of type for Cochins. I don't know exactly how many...