1) EasyTutu is available at the Pocketplane group. Essentially, it does all of the Tutu conversion in a regular-style installer. Also, when you use the base Tutu installation, you need to install a bunch of fixes. However, those come with EasyTutu. You do have to use a degreenifier if you use EasyTutu and want 3d Acceleration, but it's a lot easier IMHO. After you do an Easytutu installation, it acts exactly the same as a regular Tutu installation - it is exactly the same but with a different installer.
2) They get royally messed. I would get rid of all the Weidu mods - the patches are required, and Baldurdash has no effect. Many BG mods are available in Tutu versions - except Fields of the Dead, which I really want to play.
In any case, uninstall all the mods, and use Tutu (or BGT) on a relatively clean (plus patches and Baldurdash) install, then install other mods after.