EB0.74 will ONLY work with RTW1.2, and EB0.8 is designed for RTW1.5 (but will work with BI...though that's another topic entirely).

M2TW is a completely seperate game to RTW and will be installed to a seperate place (or directory) on your computer and won't affect your RTW folder(s) in any way.

So if you have EB 0.74 installed and decide to install M2TW, don't worry it will not affect your EB game at all and you can still play each of them without problems.