Hey JasonW,
So I am actually having some trouble getting the Media Player to playback my video within 4.10 in a new blank project on the Mac I am testing. I am going to continue to investigate this issue, but in regards to assisting you controlling your own playback in with your Media Player, I created a simple tutorial on our Wiki which you might find helpful. I am using overlap events and created a blueprint containing a media player reference variable. This works pretty well, and is simple enough to be modified to have a bit more functionality.
Media Player Asset Tutorial
Let me know if this was helpful at all. I am going to continue my investigation with this issue and will report back with my findings.
Thank you,