On my T6i whenever I connect to my cell phone or tablet using Canon Connect it blanks out the LCD screen of the camera. Even if I press the camera icon button as you would to use the LCD screen to shoot on the camera itself the LCD will not come on.
I have used the remote shooting feature in the Canon Connect app and my Chromecast to stream my phones screen to my TV. That gives you two video sources to look at if that's all you're trying to accomplish. Now that is all dependent if you are using an Android phone with I believe Android 4.4 or higher as the cast phone screen option in the Chromcast app is still beta and only on work with latest versions of Android. I have no idea if other casting devices like AppleTV or Amazon Fire Stick can cast in this way.
Hope that helps.
John
