So now it is going to become a tree rat terrorist? Coool.
Don't underestimate a dog's ability to learn a tasks they were not bred for. I got a mixed breed from the Humane Society 9 years ago and she is the most versatile hunter I could imagine. She is at least half sheltie so she is more sight oriented for herding, but she has learned to get her nose down and follow scent when she picks up on pheasant or grouse. She's no pointer or retriever, but when a bird drops she finds it, lays on it, and picks the breast clean for you. She has a natural desire to tree squirrels, but what dog doesn't??? Rabbits are a passion for her and all I had to do was to teach her to stay closer to me so we could have a chance at a shot or two.
Obedience training thru the local Kennel Club was the first step and should almost mandatory. She learned good manners and I even learned some of it myself. Basic obedience training helps in the field for recalling a dog, making the dog heel at critical times, and getting her to stay when necessary. I used the stay command so much with her that I could leave her on a downtown street corner for up to half an hour without her breaking. That came in handy for a turkey once. She lay at my side motionless while over 40 hens, jakes, and gobblers milled around us below the roost tree. Mind you she was vibrating like a cell phone on speed dial! If you get the basic obediance commands nailed, and I mean firmly nailed, then she will not go far wrong in the field. The foursquare foundation is Sit, Stay, Come, and Walk at Heel. That's also the order of importance too.
I saw a hunting show where a guide had trained his wife's Parson's Jack Russels Terrorist to point, flush, and retrieve woodcock up in New England. I couldn't believe it, thought it would be easier to train a salmon to play piano!