[tjoff]

1) Lots of desktop displays provide picture and high power, but very few laptops (and rarely even desktops) can provide any significant power from their ports (can be done of course but it is a cost thing).

2) I'd say yes (if the iphone supports it). Biggest caveat in my mind is whether the iphone allows enough current to drive the display.

3) Doubt it.

4) That is how these normally work, I don't know but that would be my expectation.