When opening the file I also get the warning message saying I'm missing the "LILO.InDesignPlugin" but the template still seems to open no problem.
Your InDesign installation is clearly corrupt. Uninstall and reinstall.
It may be sufficient to rerun the installation without uninstalling, but it might not.
Thanks for the suggestion! I figured I might have to do that, but thought I might exhaust all other options first.
LILO is apparently an optional plugin, so before you reinstall, run extension manager and check that it's there and enabled.
Ah yes. For clarity, "optional" means you can go into Extension Manager and disable it, not that it is something you can choose to install or not install. Essentially you should never disable any of the plugins that ship with InDesign unless you have special knowledge -- doing so will cause the program to fail in weird ways.