Hi @vFouad ,
Running into the same issue with a clean install of vsphere 7.0.3f and vreplication8.5.0.4. Hosts can ping\resolve each other + vcenter.
Port 31031 is accessible, services are running. Only thing is we are using local datastores so your question if all the hosts can see all the datastores, no they cannot. Documentation said this should be possible.
Only thing I notice is that as soon as I setup replication for the vcenter it tries to install a certain vib, Or so I assume, but the install fails everytime. There is only a indication in the logs about accessing port 80 with a certificate which fails its handshake. What would be weird since normally services on 80 are http and do not require ssl\tls.