Unfortunately I think the shield tv is a better buy..
Probably has issues with drm similar to AndroidTV on the raspi
No. Not unless they can run Netflix drm.
I have been looking at similar boards for a car project and came across the geekbox, which seems like it might be a better fit for ATV. http://www.geekbuying.com/item/GeekBox-Open-Source-Cross--TV-BOX---GeekBox-Landingship-PCBA-369345.html
Probably, but it's $239 and that's before you get a box for it and a remote. At that price, a Shield is a much better and simpler option.