1. Yes.

2. I don't think it can be automated, because several of the repositories have
"lucid" or whatever version adjective in the name. However, you can save the
repository list (/etc/apt/sources.list) as a text file, and use that as in
indication of what you need to do.

I have run into the situation where I installed a new version, and there was not
yet a third-party repository for that version.

I always manually edit the get-selections list, so I don't re-install programs I
have lost interest in. Also, about a third of it is lib files, which are
automatically picked up as needed.