That's what I usually do: using 2 vlans over the same bond add the benefit that if you ever need to separate the cluster network to a different bond, no Ceph configuration changes will have to be made (i.e. add the cluster network and restart...
During PVE install, the ISO installer will try to get an IP from DHCP. If that succeeds, it will configure that IP as static for vmbr0. As you are not very experienced, I suggest that you create a DHCP reservation assigned to the MAC of your PVE...
Wouldn't it be more precise to say that PVE on DHCP isn't supported without other tweaks even on single node setups?
Some services require to resolve the host name to an IP that is currently assigned to the host to work properly.