I am NOT an expert but kind of agree with your husband that the hallway should not be part of the tray ceiling.

Let's see what the experts say.

Your husband is correct. The tray ceiling should only "center" in the dining room portion of the space. It will define your dining room.

Kudos to your husband - he's correct.

I agree and yes the light needs to be centered over the table and in the tray to really look good

I question putting a tray ceiling there at all. I would consider forgetting the tray due to hallway and center junction box for light fixture over where you table will sit.
Another possibility is to put a coffered ceiling in the whole space designing it so you have junction box in center of where your dining table sits. I will see if i can find photo for you.

Here is photo of coffered ceiling uniting two spaces. Imagine the space between the family room and dining space as a hallway. Covers whole space, you have interesting ceiling and you can design it so, as in this case, the chandelier is in a good spot for hanging properly.

This approach would mean, just put the ceiling in as high as you can all over the space, and the "coffered" detail is added at the trim stage of your build.

P.S. A tray in just the dining area, will make the whole space look closed in IMO.

your hallway could be the height of the edge of the tray, with the higher tray part centered in the dining room.