1. Sorry for the confusion. Since this is a cluster question, I assume we're talking about SAN storage. An ESXi host could still have access to a SAN-based Datastore regardless of which vCenter that host resides in. So you could be connecting the Datastore to the host after it is moved to the new vCenter and then avoid copying the vmdk folder from one Datastore to another.
2. I have been working with vCenters at different sites. I think I misspoke previously. A cross-site vCenter vMotion requires the EnterprisePlus license. You said it is a lab, so these are at the same site?
3. There is no "vMotion license". I assume we're talking vSphere 7. Standard, EnterprisePlus. Formerly, vSphere 6.5 had a non-Plus license with less capabilities, the Plus version gave cross-site vCenter vMotion. But with vSphere 7 the non-Plus license is longer available. Look here: edition-comparison
P.S. I'm not up-to-date on vSphere 8 if that is what you are playing with.