ESXi 6.0 in cluster & migrate the VMs from standalone ESXi 6.0 hosts (Shared nothing vMotion)

Hi

We have a few VMs which run only with ESXi 6.0, as of now all the VMs are running with standalone ESXi hosts. We are preparing 2 ESXi hosts in HA. We also have 2 X ESXi 6.7 in high availability and vCenter to manage them. Below are our main concerns

Can we manage the 2 X new ESXi 6.0 with same vCenter?

Can we add the 2 X new ESXi 6.0 with multiple vCenter servers?

How can we do a shared nothing vMotion with those VMs on standalone ESXi hosts?

Is there a way to restrict access for the new ESXi 6.0 clustered hosts for the team managing those ESXi hosts and VMs? (we want restrict them from manage existing ESXi 6.7 cluster)

Thanks in advance