So I'm working on fixing a lot of logic holes in various Mages' Guild quests, which means a lot of dialogue editing. When I load my .esp up in the CS, however, I get a lot of "Previous string is different" and "Following string is different" errors that I would not expect, given that only Morrowind.esm and Tribunal.esm (for the journal) are loaded. Is this harmful? I know it doesn't make a difference when it's caused by Tribunal and Bloodmoon being loaded at the same time, but with no Bloodmoon it's a little worrying. If it is bad, how do I fix it?

The workaround to get rid of the error messages is to add the following
line to your morrowind.ini file:

AllowYesToAll=1


But im pretty sure 100% its not guna affect anything ingame.

But you should really always make mods with all expansions running these days

I would open the esp in TESAME or Enchanted Editor, and look for any weird changes to the dialog that you did not intend to make.
If you see nothing odd, then I wouldn't worry about the errors.
(although it is odd that they appear with just Tribunal)