Hey jmok -
I. In bullet 1. above you ask "Do you want to enable extended display?" Actually, that's exactly what I want to do but don't know where to start. I'm working with the u820 at the moment, but would guess the answer is similar whether employing the 626 or 820.
II. My application requires different resolutions and potentially different orientations between primary and secondary displays, though I do have some flexibility as to which channel (DSI or HDMI) is assigned to which priority (primary or secondary). You've already said that the orientation issue should be directed to the helpdesk - same for differing resolutions?
III. Looks like there's a new LCD accessory for 626/810/820 dev boards, but I can't find any specs ... can you share basics, like size, resolution, whether it has embedded touch? (controller IC would be nice as well)