I would hang them all at the same height with the rod just skimming the top of the window, creating a waterline around the room...ignore the ceiling height.

Do you have a window in the upper portion of your foyer? I have a two storey foyer and we simply centered the chandelier on the window. As far as height over a dining table, I'd think that regardless of the height of the ceiling, the regular "rules" would apply. I've seen a bunch of different sources for chandelier size and height. I've put a link to one below Here is a link that might be useful: Chandelier size, height, etc

You want clearance overhead, so I'd say the bottom of the light should be at least 7-ft above the floor that is below the light. Beyond that, I think it depends on how it looks. To me, your light looks like it should be moved up maybe 6-inches.

I don't think you want the fixture any lower than the top of the door frame. Subtract the door height (120") from the ceiling height (244") and that puts it at 124" above the floor. That 's the distance Beverly is asking about. You'll want to reduce the fixture's height to 120" or about 10'. by my calculation. Please double check me first though! I would also suggest you place a round foyer table in that curve to the right of the stairs, since you don't have room for one centered under the fixture.