Replication and linked server security
I just reviewed the replication on one of my clients systems and I see similar linked servers both on the publisher and the distributor.  In my case the linked servers are all setup using the "Be made using the login's current security context".

If you've got the linked servers setup using a specific security context that's probably because the machines aren't on the same domain.  If they are, and the rights are setup correctly you can try changing things.  The linked servers should only be used when making changes to the replication configuration so if there's a problem you may not see it until later.