@kenchan - Again, thanks. I've successfully used -Wno-missing-braces on the analyzer and editor, so it 'works' for at least some versions of the compiler.
As for 'warn_on'/'warn_off', I had no trouble verifying their existence/function once I found them in the .pro file, but I had no prior warning to look for such a thing. I've been looking for QMAKE_CXXFLAGS, not weird macros that are defined in some middle ground between the .conf files and the .pro files. I don't understand how the .conf files work, much less how to successfully invoke half of the options documented there and elsewhere.
On the other hand, I think that I've solved my main issue with the discovery of the hidden 'warn_off' in my library's .pro file. I have compile warnings again. More than I'd like, true, and I don't seem to be able to turn off specific warnings, but fixing the autogenerated code should get rid of the majority of the offending bits, so I can at least have some confidence in my builds again.