Glad you got your expensive tome out - wondered where you were. Interesting stuff. Fishbase only show these two in the Variola genus. Maybe there is another lurking undiscovered.... or even viable hybrids?
Stunning detail and agree, a beautiful fish. Both have the violet/blue spots and the overall colour can vary tremendously. Both can display saddles according to Fishbase but not always. I am sure your is correctly identified.
I'd go for White-edged Lyretail - Variola albimarginata. However, it is very similar to the Yellow-edged (V. louti) with I think the only distiguishing feature being the tail margin. Given how groupers as so adept at changing their colours, it is difficult to be 100% sure. The white stripe between the eyes is a feature of juveniles of V. louti - not sure about V. albimarginata.
I am sure they are bubbles caused by your pump/filtration system. I used to do a lot of pool work photographing babies commercially at various pools around the UK. Most were OK but then one would cause the trouble you describe which it hadn't done some weeks previously. Switching the pump off at the beginning of the day when it was first noticed did start to make an improvement several hours later but then, due to the throughput of babies and parents, the water started to go cloudy. I could handle that but the bubbles were a nightmare just as you describe. One pool engineer was very helpful and he explained that when the bubble syndrome occurs, it is because the pump needs servicing. He said that over time, the pump o-rings wear and get slightly sloppy which allows air to be introduced into the water via the pump. I think he was right because we had to abandon one shoot as the problem was so bad. We went back a few weeks later after a pump service and all was hunky-dory.