@Brooks,

Are you able to create RPO plays in the advanced settings additional plays XML?
And/Or can you create RPO plays in the Custom Play Creator
I do not see an "RPO" option in the custom play creator only run or pass.
But looking at the Plays.XML it seems you could add RPO plays with the "RPO" Command in the additional Plays XML.
Can I assume that all of the above is correct?

Sure, you can add them to the xml if you want.