Thank you Cipher for the quick reply. It's really appreciated. But just to be clear, are you saying that if I purchased all of FSDT airports, they will all load into the sim every time I start it just because they are initiated by the exe.xml file and not the addons installer? If that's the case, then that's a ton of unnecessary scenery for MSFS to load and that's going to extend the load time by a lot. Perhaps FSDT should consider not using exe.xml to load their products so their customer can pick and choose which scenery is to be loaded at any given time.
The FSDT airports do not use couatl, and are thus totally unrelated to the exe.xml file. The exe.xml file is used merely to load the couatl executable which is required for GSX operations. So my advice is just forget about the exe.xml file, and unless you know what you're doing, don't touch it.
I use MSFS Addons Linker to enable/disable the FSDT airports just as I use it for all other scenaries. This can be easily accomplished within the AddonsLinker... go to the Options General tab and add a new Addons folder, which points to the install directory for all your FSDT airports, these airports will then appear in the Community Addons panel on the left of the app. Indeed you can also enable and disable the 2 GSX folders since these 2 folders will now appear in the AddonsLinkker app, although by default the AddonsLinker uses Junction links, whilst the FSDreamteam uses symbolic links to link the GSX folders into the Community folder.