Wow, I'm just so impressed with the sharing, generosity, and commitment of the folks here to help others out. I LOVE YOU FOLKS!
Congrats to those who are having problems and who have the great good sense to consult to the many knowledgeable people in this thread. It is a great idea. So many medical professionals may mean well, but really don't have the detailed experience nor interest to delve into the differentials of people with these detailed issues.
I have been so lucky with my vaping experience -- the down side is that it makes me useless to the folks who are having trouble

I have no allergies at all, and have had no problems at all with the switch from cigarettes to vaping, so I am just pure LUCKY. For many many years of smoking, I was smoking the American Spirit ultra-lights, and they are supposed to have no additives (though they probably have a few, such as the ones to the paper that makes the paper not so flammable). I don't know whether that helped or not in making the change.
About E-LIQUIDS -- it is weird to me that the only list of faves I've managed to come up with so far were the MBVs -- since when I first bought any of those, I really truly suspected that I had been fooled by the hype.
BUT -- that is not because MBV is my fave vendor -- not at all. I have NLV, Nicoticket, Highbrow, Ahlusion, Pipe Sauce, The Vape Tree, VaporZone (though that one is going negative, so far), The Vapor Chef, Mom & Pop's, and at least 4 other makers to work on. It's just that on those, I haven't tried enough of them, nor often enough, to come up with a postable opinion. Definitely a few of those I've tried have a flavor or two that I love, but I want to try more before I say anything. It's just that MBV was the one that I tried so dang many flavors of, that I figured I had come up with a fair evaluative opinion of my faves. More non-faves than faves for MBV, for sure.
I am so sympathetic to those having issues with vaping, and so proud of everybody trying to help!
I keep holding off on trying HHV (Heather's Heavenly Vapes) and AiV (Alice in Vapeland) because of all the hype, and because there are TOO many flavors from both of them that simply SOUND so good. I fear placing an order because I will likely overdo it. I've seen plenty of negative posts on them both, so I thought I would try the slight-outliers first.