I haven't used EF against anything but MSSQL, so haven't ran into what you've experienced. Although I'd be hesitant to use it with something else, there's no way you'd get the deep integration with a third-party database server. But for solutions based on MSSQL, there's nothing better I've seen in any world.
3. Usually when I run into issues like that, I'm doing something stupid. There's a few cases (Like working with Full Text Search) where I drop back and use a stored proc, but 99% of what I do, EF and Linq has not let me down.
5. Check your project configuration, you can set it to push out the same version of EF that you used for development.
6. Who the hell is modifying the database schema in production without going through proper QA? That's a management issue, not an EF issue.
7. See #5