Doing the same chandelier, but smaller, in the dining room will look just fine. No need to complicate things. I had to find complementing fixtures for an open plan and it isn't easy! I didn't have the option of a smaller/bigger version of the same style.

IMO those kitchen ones are not ideal since lighting the island is IMO a must so not lighting the ceiling is my first thought . IN fact all the lighting I see is lighting the ceiling not the space . IMO the DR light can be the star and . not have to match the rest .

I like the light fixture in your den - and I think using a smaller version would be fine over the dining table.

I have a request - would you mind adding a photo of your fireplace (taken straight on in front of it) in a comment? I am redoing four fireplaces - and would really like to get a better look at yours!

With the timbered ceiling, I don’t think you need the Darlana pendants. I would replace them with dimmable recessed lights. Your chandelier looks great.