@AOKP thanks, will try to see if I can come up with anything.
As I was researching this more last night, I began to realize one of my biggest questions is this: I understand fairly well how each app is set up on its own. LAMP Wordpress setup using Apache2, MySQL, and PHP - I understand that. NodeBB setup with MongoDB - I understand that too (still trying to wrap my head around Nginx, though, as I've never used it).
What is making me paranoid about screwing up somewhere is whether or not I'm making the right choices as I plan to link these two apps. Should I keep Wordpress running on Apache2 and NodeBB running on Nginx or should both just use Nginx? Should I try to make Wordpress work with MongoDB or just go the standard route with MySQL and leave NodeBB on MongoDB?