I use a second monitor to put graphs. It works so much better than an overlay because I can see the history of about the last 5~10 minutes.
If you really want the overlays though you can disable Origin in Game. By disabling OiG you can no longer push Shift+F1 to join friends games quickly and cannot use the coin shop.
This is true for about all overlay programs like RiviaTuner or fraps.
#2 seems like a decent answer. I remember doing something like that about a year ago but can't quite remember why.. OiG is a good bet though.
I wouldn't want to go back to overlays with a second auxiliary monitor now. So so handy for graphs, IRC chats, voice comms, a browser window, anything you want.
This game doesn't lock the cursor in fullscreen mode so this toolset is handy.
http://dualmonitortool.sourceforge.net/
Here's a forum post describing it for this exact purpose:
http://www.neowin.net/forum/topic/1146484-how-to-lock-your-mouse-inside-a-game-on-a-dual-monitor-setup/
