Victoria Stillwell started as a Dog Walker, she is more for positive rewards. I train that way, though there are times I have had to apply some tough love. Karen Pryor, Ian Dunbar, Sophia Yen are ones I would suggest you look up.
I compete and show professionally, my dogs are taught to Heel and "release" means they go out in front as long as they do not pull. Wish I could show you that! They can smell and be a dog, however, when I say HEEL, they must come back to the Heel. It really is advanced training. My Blue Aussie just titled in Rally O!!
As for Dominance, remember it is only Species to Species. Most owners confuse it and will tell me thier dog is Dominant. The dog seems that way because they have rewarded bad behaviour, I see it all the time. I had a full grown Pyrenees who was herding the family and growling when they moved. They called me in desperation as poor Sparky was headed for the Dog Prison. I spent two hours getting him to understand he could NOT jump in my face and do that. He had been rewarded by the family when they gave into him. This has a happy ending. After several sessions, the family started changing thier response to him. He is a different dog now!
The best advice I can give right now is to study your breeds, if I didn't have a understand of Pyrs I could not have turned the situation around. One method does not fit all. Yes get your Vet Cert, I suggest if you can, work for a short time as one. If you have to work evenings and weekends, it will be worth it.
I have done this so long, I love it. It's a great to see happy endings and happy owners. I too had to work for years as we needed a steady income. I'm 55 and can now do this at my leisure. So yes get all the training and experience now, one day you two may be able to do the same. Good luck to you!!
Also check out Victoria Stillwells site and her blogs...good info there!