That depends on the language. Aside from languages that preserve the accent placement itself, there are also languages that preserve indirect traces of the accent. Verner's Law in Germanic is a good example of that.
I don't think they did. *mīnaz probably goes back to an earlier *meynos, but I don't know where that came from.
Last edit: 22:18, 28 May 2014
As far as I know *-nos forms adjectives from verbal roots, but I'm not aware of any other use.
Could *éy- have been a verbal root besides a pronoun?