On your previous thread - the one in which you announced that your collection was being hit with the RI - both Deborah and Mpkeelee advised you to discontinue the baths immediately. That was the correct advice.
Any breeder, be they high end, low end or otherwise, who recommends bathing or soaks as part of the recuperative regimen for an RI, should be ignored. It is not only bad advice, but dangerous advice. You need to cease those soaks immediately. If any "high end" breeder thinks I'm full of crap on this issue, I would welcome the opportunity for them to sign on here and debate me directly in OT.
Better yet, why not name those high end experts on this thread so that someone else does not fall victim to this horrible advice? I cannot stress enough how incredibly dangerous and irresponsible these soaks are.
Now with regards to your vet - most respiratory infections are caused by an over abundance of common bacteria.
The reason why a snake succumbs to common environmental bacteria is due to a compromised immune system. A snake's immune system becomes chronically compromised when they are either stressed due to poor environmental conditions or due to an underlying pathogen - like a virus.
Flatly put, if you accept that your vet was correct in his diagnosis and there is no underlying pathogen, then there are stressors that are compromising the health of your animals (like soaking them). You can either review your husbandry practices or your can take the animal back to the vet, and see if the vet is on the ball enough to test for something systemic or if the vet asks you some hard questions about how you are keeping your animals.
Your vet was quick to finger the substrate as the cause. Now that you have replaced the substrate, it can be safely eliminated as the reason for the problem.
When you stated that your vet found three culprit bacteria, a ton of questions came to mind. How did the vet conclude that each of these bacteria was overabundant? Are each of these bacteria capable of causing an RI? Did the vet share with you the name of each bacteria and why the antibiotic was being prescribed?
Whichever way you decide to go, there are no residual symptoms associated with an RI. No amount of drool or chronically labored breathing is normal. My advice remains - cease the soaks immediately and get your animals back to a vet immediately.