After a couple more compiles and tests, same false positives and after a tad of research it seems these are inherent to the 0.13.xx branch I chose to fork:
https://github.com/bitcoin-dot-org/bitcoin.org/issues/1472I chose 0.13.xx as the "latest stable," but may have to re-rebase it again in the long term. Going to try a couple more compiles and build a fresh VM from scratch just to be sure--if nothing else works, I'll post links in the next 24 hoursish.