I would be guessing about the causes of the sneezing I would keep a very close ye out for RI as it is a possiability. I have never had one of mine sneeze sometimes one will exhale heavity. (huff) but past that...

What I see with you set up is two things. your hot side temp is quite hot if it is accurate. 94 is usually the hottest most would recommend and personally I don't like seeing over 90. The other thing is the fogger. I see no problem with it exactly but I'd likely allow the temps to come up to day temp before misting as you have a drop at night and the fogger is likely to drop it further I'd suggest that at the it should be used during the hottest part of the day and then off.

The next question is how much ventilation do you have? Lots or little? High humidity and low ventilation is known to create prime RI conditions.

I would not suggest a blast with antibiotics but rather a culture be done and pointed drugs used. Not just broad spectrum stuff.

Keep an eye on things to be sure it is not RI if it is get to the vet.