I would go with a male cat. From my experience, there's a greater chance that two females will not get along. Of course it's possible, but if it were me, I'd just go with the safer option of getting a male.
I don't think your schedules will be a problem for you to get a Bengal, especially since you have other pets to keep him company. Granted, your girl may not be able to keep up with the Bengal in terms of active-ness, but I don't think he will be lonely with dogs if they get along. Some Bengals do require more attention than others, so you may have to time play sessions in the morning before you go to work and at night when you come back, if he so wishes.
I'll let someone else answer the Tennessee breeder question.