Your first comment was about the humor of MI being awkward now. Outside of Fallout, none of the games you listed have much writing in them, let alone humor. They are all still great* because they have such tight gameplay.

* Love Fallout, but it's probably the hardest game to go back to out of the list you gave.

Yes, you can't have the voices with the old graphics in MI1 Special Edition so you need the hack. Unfortunate oversight since I think many people would like to enjoy it that way. I believe they made it possible in the MI2 remaster but never changed this for the first one.

It does switch voices. But also we were playing on a platform not supported by the remastered version, so we needed to use ScummVM anyway.