First, the licensing discussion is really one you should have with your account team - any answers you get out here are not legally binding by any stretch. That said...
2. When you install Unity you can apply one license - it's either UM or it's VM - there's no mixing at this point (this is something to bring up with your account team if you'd like to push to have mixed UM/VM supported).
3. No - if you install VM only you are fine if you are not using TTS (which wont be allowed in your COS) and you are not accessing voice mail from any desktop application other then the seperatey licensed web inbox from Cisco. That's it.
5. See answer to #2 - there's no mixing supported at this point.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...