Mmm, I'm not sure that the Cathedral "must be related" as such to MT, and likewise for Temples and Cer. If you look at the FW MoMJr. scenario (which is full of educationally-valuable bugs), you'll notice that the designers rather sloppily made MT into one of the Sorcery techs, but had Cathedrals and Mike's Chapel built by some other tech. The result? Cathedrals work fine for Jafar once he's discovered that Sorcery tech, and do nothing for anyone else unless they've begged/stolen/gone to the incredible trouble of researching said Sorcery tech.
So I'm pretty sure MT and Cer don't have to be prereqs for the two improvements, you just have to have them for the Cathedral or Temple to do anything, even if you have Mysticism or Theology. Maybe that's what you meant by "related," but you might want to clarify. You can make it "unrelated" rather handily by making MT and Cer into nonos and giving them to some but not all civilizations, thereby making truly civilization-specific improvements. I imagine the same holds partly true for Radar and Airports, in case you want to give a city veteran and quick-healing air units without the airlift ability.