I know you said your cages meet AWA minumum requirements but I go by American Rabbit Breeder's Association standards (their minimum requirements are slightly larger than AWA standards) and by own experience. I've had a FA before and the 24x30 hole he came to my home in was the minimum I'd keep a FA buck in. I like to give breeding does need even more space for their nest box and litter and add a floor support. That is my preference.
It sounds like cleanliness of the air or confinement in an unclean environment is not your problem. I admit that I'm not understanding your process for testing for or finding pasturella free stock as most rabbits will test positive for it even if they will never get sick with it in their lifetime.
As far as turning a profit, all I can say it that rabbits are not really money makers. My friend Betty Chu who raises and shows English Angoras gave a seminar on the Angora Cottage Industry. If you know Angoras, you probably know Betty as the "famous Betty Chu" but you might not know that she also has a PhD in ecomomics and taught the subject at SJSU for many years. While *some* actually make a reasonable living in marketing/selling angora to textile buyers of large companies and individual fiber artists, most can only hope to pay for feed from selling their stock and products - and that is wonderful. I'm really not trying to sound discouraging, just realistic. Turning a profit on rabbits will take much time and work if it's done right but will be worth it.
I really think you ought to go to a few shows once your feel your rabbits are up to it. You'll only learn a lot. You'll know how your rabbits stack up to the others in your area, you'll get helpful comments on both the strengths and weakness of your rabbits, and that will help you to decide how to breed better stock. And, if you do real well, grand your rabbits and network a little, you will be better able to know what price your stock warrants and probably find a good outlet for your kits. It will help you to learn more, give you a chance to build a good reputation, and broaden your market. Having good, winning show stock to sell will help you be able to ask for more reasonable prices for your kits instead of having to settle for something less. If you decide you don't like shows, well, at least you can take home the knowledge you gained from the judges and other exhibitors.
One more thing, re-reading the symptoms, "clear damp" would not worry me at all. If the lungs sound clear, I'd expect any damp to clear up quickly. It is enough to be alert about but not much to worry about yet. As you said, true cases of Pasturella and/or wry neck will show more than just a damp nose or paws.