Help Itunes Media Library died - will iTunes match work? - I haven't subscribed yet - If I load the dead library - still has a list of my music - but obviously can't play it - and cut it down to the match limit (I have lots of bad music) - will it bring back my iTunes?
Also what happens if I end my iTunes match subscription?
This is a big, "It depends." There's more than one possible cause of death for an iTunes library, though "still has a list of my music" at least suggests that the music files got moved, and therefore can't be found/played.
When Match searches a library, it's looking for music both known, and unknown. Perhaps it possible for Match to identify the known contents of the library based on the data that you can still see on the screen. What Match wouldn't be able to do is upload the music that does not match the contents of Apple's music library.
I can't tell you how Match behaves if it encounters a problem. Others may have an answer. It's likely, however, that it can handle some kinds of problems well, and may choke on others. So without knowing what is wrong with your library, we'd all just be guessing.
What happens if you leave Match? The music in your library that was purchased from iTunes remains available, as iTunes in the Cloud - you'll still be able to play it. Music in your library that you copied from CD? That won't be available from the cloud, you'd have to re-sync it to your device. And if someday you decide to return to Match? Match will re-scan your library. As long as the music is still there, it'll be matched again.
I know I know are uploaded, so that would be my obscure cast recordings of shows and some non major record label stuff - but for the majority of items ripped from mine and my dads cd should match them?