Help configuring MySQL install for remote connections / root accounts understanding
root@localhost allows a root user to connect to mysql locally from the DB server using the mysql socket file.

root@127.0.0.1 allows a root user to connect to mysql locally from the DB server using the TCP/IP protocol. (Trust me, you will be needing this one. MySQL has a nasty bug in it. The bug sometimes causes the mysql socket file to disappear rendering root@localhost useless. You will need to connect using root@127.0.0.1 if this ever happens to you)

root@server.domain.lan allows a root user to connect to mysql from server.domain.lan using DNS (Dynamic Naming Services)

You could create root@'%' but I highly recommend you do not.

I would also recommend using a different password for each root user.