I'd say this is the more correct response :) you shouldn't need to unprovision the Guest in order to perform VLAN operations.
You could also create the VLAN on the Guest first, create self-IP objects, and then modify the tenant configuration from the vCMP Host adding the VLAN subscription. As long as the VLAN tags match, it will work (even with different VLAN names, as long as there isn't another VLAN on the Host with same name but different tag).
When you remove VLAN from the Guest, it's a little tricker and you should perform a specific set of operations, since removing it from the Host will remove the VLAN subscription on the Guest but won't delete the network objects, nor the self-IPs. You'll have to do it manually afterwards.
Try checking this: https://techdocs.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/vcmp-administration-viprion-13-0-0/2.html