Is there anything special i have to do when restoring a backup from another system to a new MCS server? In terms of licenses?
With Business Edition you only have one server so that is effectively the Publisher therefore you need to get the licenses (CUCM and Unity Connection) re-hosted.
Is the server you are restoring the Publisher or another node?
If it is the Publisher you will need to get the licenses re-hosted with the MAC address of the new server. Do a restore then upload the re-hosted licenses and delete the old ones.
If it is another node you should not have to do anything other than the restore.