Open this page in Firefox. On each video tap play, then YouTube's full-screen button at the bottom right. Note the numbers that open the full screen.
WordPress's own YouTube player, exactly as on multiconex.com.
Like 1, from the privacy address we use.
Like 1, with the setting that lets the page stop the sound.
Like 1, with the setting we use for the full screen.
Like 1, with the play button alone: tap play only.
Like 1, with our frame's permissions.