The arp -d will remove any entry from the local ARP table, which contains the MAC address related to the IP. If the IP changes, the MAC "cache" is wrong for max. 60 seconds (which is the typical lifetime of ARP entries). So the second one is correct. An flushdns would only help if the IP address does not belong to the DNS address used any longer.
The first one helps indeed. However, the server should announce itself fast enough to make nbtstat -R superfluous. But it is not wrong.
NbtStat caches the NetBIOS information - who is Master Browser, which NetBIOS services are propagated. With AD those information is stored there, with DNS entries, and then, and only then, a flushdns would help.
