1. If you add the video using the video element, it will be center align on the page.
Since you have added it in the page, it will take its own CSS and display the way it is. Hence, there is a video element feature in the theme.
2. There is no option to size the video. The video element will make the video full width on all the devices.
Regrading the file info, it is the the tilte displayed on the youtube page for that specific video. if you dont want to have that title please add below CSS