LACP is supported on the vDS only. I'm guessing that when you move one uplink to the VSS you'll need to configure the physical port to remove it from the port-channel. Essentially do the reverse of what is being done in this article:
It is possible to have a LAG on a VSS, but only IP hash is supported for load balancing and I don't think you can be using LACP. Since you're only temporarily moving to the VSS to migrate between vCenters I wouldn't bother with the additional complexity of configuring a LAG for the VSS.
I think your procedure looks correct.
Thanks for the reply.
I too believe that physical port to be removed from the port-channel, but is there any vmware article or KB to confirm this?
I found this William's post https://www.virtuallyghetto.com/2017/11/moving-esxi-hosts-with-lacplag-between-vcenter-servers.html that says it can be moved just like that to VSS without removing physical port from port channel, but this never works.
Interested to know what is the VMware supported way of doing this.