Flavor art has a lot going for it, including the fact that they are fairly strong flavorings so if you wind up liking them, they're useful for DIY.
I'm afraid getting a flavoring company to tell you if their flavors are dactyl free and whatnot can be hard. Some known general offenders (I think) are (many) vanillas and some cinnamons, but for the most part, it can be a bit of a black box.
To be fair, the studies showing harmful byproducts, not all of them were extremely well done, and the dosing and heat you'd need would be pretty intense to cause your flavors to degrade (again, this is my opinion only). I can't
vape vanillas, they make me hoarse, so I don't use them.
But, I also don't worry too much about it, I think in the quantities they are usually used in small enough quantities that any kind of risk is somewhat mitigated.
However, it is your body, so if you have concerns, I'd agree with those stating that Flavor Art flavors (or vendors that use them) may be your best bet.
Good luck,
Anna