I think you have room for a little more island, both directions. You don't need more than 36 to 42 inches traffic with a counter depth pantry style fridge, between it and the island. The doors fully open aren't using more than 18 inches!You DO want 48 or more on the stool side of the island.

It's hard to read your plan. Darken the ink : )

I'm not a kitchen designer but it looks workable to me. I love your windows. Do all you can to preserve them.

IMO a wider walkway is always preferable but not any larger than 48” for sure and I would have that size where the fridge is anyway. I do find the fridge and sink quite a distance apart

You could easily do a bigger island. I might eliminate the pantry and move the refrigerator and range down. You would gain more counter space between the sink and the range - this is where I do all my work.:) If you extend the island - it would make up for space lost removing the pantry. I do think it's a great idea to shorten the windows to gain more counter space and a view. You will love that!

quite a good layout.
I'd remove the closest top cabinets on either side of the stovetop (one door on the left and one or two doors on the right). Personal preference, I like space around the stove.
I like wide walkways. They're particularly helpful when multiple people are working simultaneously, and great if your kitchen is, or you want it to be, a gathering spot.
If you do want to widen it a bit though, it certainly would work. Keep it as is in relation to the stove area and sink area, and extend the length to align with the wall to the living room, and the width closer to the dining room entrance as much as needed.

I don't find the distance from the fridge to the sink too far. There's a straight, unobstructed line, and the island is not a barrier

This is what 50" to the refrigerator door (and 52" to the cabinets) looks like in my kitchen, but it has to accommodate a LOT of traffic, and leads to the outside as well. I like your other walkways as they are, and second 48+ on the stool side. Would it work for you to add one more upper cabinet or open shelving to the left of the dishwasher?

I like aisles to be a bare minimum of 42". I prefer 48". I'd do 52 or 54 on stool side.

Taking into account how the outside of the house will look after you change windows, I think it's a good idea. How does your builder propose to fill in the extra space on the exterior?

That's a great question....I don't know how the contractor will deal with the exterior. Here's a couple of photos of the windows in relation to the rest of the house. I really hate to shorten them but the only designs I have all include running a counter along the window wall. Also a little concerned about the 'fish bowl' of having my sink in the front of the house but not really sure where else to put it. Welcome any thoughts.

I think siding can be matched, good landscaping will camouflage the difference in window heights, and dense solar shades (water and stain resistant) can provide evening privacy from the street.

I think the windows can be changed, and the plan you have is good enough to warrant it ;) The same for a sink facing the street. I love having the sink there by the way, but it does make a difference that the street is somewhat lower, we're on a slope. Maybe you'll get used to it?