for the first question you don't have to uninstall everything and start over.
Use the installer for Patch 1: you'll be prompted for uninstalling only the Patch. After uninstalling the Patch you'll be able to install the new one.
I can't answer the second question, but I would like to ask another question:
I saw that with Patch 1 the Monitoring Apps have been upgraded.
If we need to uninstall the patch for whatever reason, the upgraded Monitoring Apps will stop working as expected?