No, I think extending that wall would really cramp circulation space. If I've got it measured correctly there's only 4.5 ft between the edge of the counter and that post as it is. I think it would be unacceptably awkward to make traffic go around the end of that wall if it were extended. (Also, we wanted 1 freestanding post somewhere in the design of our home, but that's just a silly personal choice, not a requirement for any real reason.) Also, I think the interior views re better to be able to come into the house and see through to the stairs. That range wall is an interior wall, and can move, or be mostly removed. (Obviously the post, however, can not). The other side of that wall is the main front entry. The closets/bench will not be built as drawn. (The upper closet will go, and probably the lower closet will be a bit larger) I want a closet in the entry, and I need at least a little of that lower closet, because I have to hide some HVAC ductwork to the upstairs in a couple of places, and that's one of them.

I'd choose a flush mount option.. then, while the builder works on walls etc, I'd go on local E Bay/Etsy and check flush mount lights from mid-century modern period. That was a time of lower ceilings etc. they really thought about how to make these beautiful, as opposite to now. Some lights I saw there were really nice. They were listed also by European sellers so you wouldn't have problem with parts etc. I bought one from an Italian store, and I love it. It's not modern at all. It's very Murano glass heavy)) It wouldn't fit your purposes as you need something flatter and fully covered I believe; but just saying that checking vintage may have sense, in your case. The prices will be better too.

They are polished nickel so I do need to stay in the same finish.

I think doing a mix of different white tiles, or a mix of gloss and matte tiles might be easier to harmonize with the other two whites than having an expanse of a single white in the backsplash. These ideas are from Heath Ceramics. A mix of Heath's canvas white and vanilla bean. I don't know if I like this pattern for you, but I like the color mix. This is a dual-glazed tile; part of the tile is glossy and part is matte (I don't know if anyone but Heath does this, but you could mix gloss and matte tiles from someone else for a similar effect)