Just wondering can you connect ESXi 5.5 host to vCenter 6.7?
if so, could you stand up a new vCenter server, and migrate the inventory so the VMIDs remain in tact. (At this point I'd disconnect each host form old vCenter and connect to new vCenter) in hopes the cluster and VM ID's stay in tact. I'm aware of the normal method, just trying to think outside the box.
No, that also won't work. New morefs will be generated in vCenter's inventory for all managed objects. But, depending on what application you were interested in making use of those mappings, check with the relevant vendor because sometimes they have utilities that can be used to "repair" those object mappings (like Veeam, Zerto, others).
No, a 5.5 host cannot be joined to a 6.7 vCenter.
OK, what about manual migration of a host, lets say you already have 6.5 hosts, and a 6.5 vCenter, could you migrate the inventory data to a 6.7 host and un-join and re-join the hosts to the new vCenter while keeping VMIDs intact?
No, that also won't work. New morefs will be generated in vCenter's inventory for all managed objects. But, depending on what application you were interested in making use of those mappings, check with the relevant vendor because sometimes they have utilities that can be used to "repair" those object mappings (like Veeam, Zerto, others).