Modifying replication distributor & publisher
Changing the IP addresses is no problem.  You'll just need to force AD replication after the machine comes up with the new IP then do an IPCONFIG /flushdns on the other machines so that they can all see each other.  Depending on which machine has it's IP changed and if you are doing push or pull replication you may not even need to do that.

Moving the distribution database is a lot harder to do.  You can shutdown all the replication agents and do a backup and restore of the distribution database to the new machine, making sure to use the KEEP_REPLICATION flag.  You'll then need to recreate all the SQL Agent jobs for replication on the new machine manually.  Then you'll need to edit the replication tables manually to change the distributor to the new name, then edit all the agent jobs to give them the name of the new distributor.  Once all that is done everything should work again.

Moving the publisher requires that the same approach be taken as moving the distribution database.