Hi Dmitry, thanks a lot for the answer!
I've forgot that Veeam licensing is based on the number of CPUs in protected hosts, not on the Veeam servers or other comonents.
One quiestion that I still have is: if we go for 2 Veeam servers scenario (one for the backups on the primary site and one for the replications on the DR site), shall we face the situation with access conflict? Let's assume that one VM is backing up with site 1 Veeam server at the moment. What if Veeam server at site 2 tried to replicate the same VM at the same time? Will backup, replication (or both) jobs fail or just "waiting for backup/replication infrastructure resource availability" message will be logged, and then both jobs finished with no error?
Another approach is to have only one Veeam server that handles backups and replications at DR site, with proxies and repositories for backups at the production site, but I'm afraid in this case there will be a problem with connectivity, as we have a slow WAN link between Site 1 and Site 2 and it will be always filled up with replication data flow. So I think the Veeam Server will be hardly accessable from the VBR console at site 1 with a very slow response.
And the third approach is to wait for the Veeam Availability Orchestrator