- Depending on the number of hosts you are going to install, it might be easier and faster (as well as supported) to just manually configure the settings, unless you are using Enterprise Plus licensing which provides Host Profiles.
- There should basically be no issue with new v5.5 hosts. However, keep in mind that you fist need to upgrade vCenter Server to v5.5 in order to be able to add v5.5 hosts..
André