NodeMCU is great, and it really did make this project an absolute joy to work on - having built-in MQTT, SNTP, RTC, etc code really made for a very convenient coding environment. Oh course, with convenience come caveats, and in this case the caveats include extremely limited memory space.

After spending time on programming and hitting more and more memory limits, I've noticed that you really cannot do anything complex with NodeMCU (the ESP just doesn't have enough RAM), and this application alone very nearly exhausts the available memory. I already have had to compile the bulk of the program code down to an .lc file with the debugging symbols removed, and will likely have to do so again with the modes programming should I wish to add additional capabilities to the project in future.