Bahamian,

I like the idea of the APBT X CO as a property guard dog but I'd go in a different direction from there.

On paper it's just speculation, you don't know what you're going to get until someone breeds them. 

Let's say F2 didn't bring the right trait or quality you're looking for then it's back to trial and error until you find a breed that works better. In all it actually takes many years, hard work and a lot of money spent before you actually have a breed that is true to type and temperament. However, in the end it usually is rewarding to the person that created the breed and have something to pass on to others and a betterment of dogs as a whole.