OK, I am late to this conversation, but I offer the following...
I have a Windows 10 PC as my MC client in the entertainment center here.
For years (literally), when I power up that PC, it logs in to an account (I think it is "media" or something like that).
Once in that account I have MC configured upon startup to run Media Center.
That brings me into Theater view.
And all is happiness from that point going forward.
Unfortunately, if you now ask me how I got Windows 10 to auto-login, I could not tell you. And yeah, as I now type that, I realize that I blew disaster recovery step (a major one).
So now I am now reliant upon the Macrium Reflect for disk images in case I need to undo a change. Majorly unfortunately, the great Macrium Reflect no longer seems to have a free license for home use. That's a shame.