There's no real rule per-se, but I like to keep the fixtures close to the same shape. I don't like to mix squares with round, and that's just my "thing". I've worked with designers who feel the same.

Also like #3 best. It looks like your ceilings are at least 9 feet in the dining room. If they are the same or taller in the foyer, you should be okay, but If the fixture depth is too tall for your space, it may come with a fixed ceiling option that eliminates the chain.

I also like to match up the shapes if not the exact fixture in a different size.

I like the first one and see no trouble in mixing round and square/rectangle shapes. Artistically, different shapes add interest.