Wow, that's a nice design. The only thing that occurred to me would be moving the DW over to the right of the sink so it's closer to the dish cupboard?

deedles, if she does this, then when the door is open, she won't be able to reach into the cupboard as the open door will be in her way.
How big is the pantry-how wide and deep? If it is deep, will it have pull outs? If not, GET THEM!

Personally, I'd move the prep sink over to be above where the 2 cabinet doors are showing with the drawer. Say you are taking stuff out of the fridge to make a stir fry. Sauce, 8 different veggies, raw meat. Is there going to be room for all of that on the edge of the island with the prep sink where it is? Also, if you or anyone using the sink is left handed, it will be a big adjustment for them not having any space to their left to place things. FInally, think of how you prep. I work left to right. So I would have the bowl of unwashed strawberries on the left of the sink, wash them and then place them on the cutting board on the right of the sink. WIth this design, there would be nowhere for me to put my bowl of strawberries. I'd have to have the bowl on my right, wash and then return the strawberry to a cutting board that is also on my right--but what if the bowl of strawberries is rather large. Then I'll be reaching over the bowl to reach the cutting board to place the clean ones. Just something to consider. Everyone preps differently, though.

Okay, had to review your pictures to make sure. I see that your island counter ends in front of the frig with an aisle.

1. Is that aisle space big enough that you can have the frig sit there before the last push back?
2. Is that aisle space big enough that you can pull the frig out if a repairperson needs to get at the back of it?

If the answer is no, to these two questions, then you need to reconsider the size of your island since you already have the frig.

Great presentation of your plans. Very easy to see how the pieces fit together despite no floor plan.

The biggest negotiation you had to resolve obviously was placing the frig that far from the sink. For the household you have it will probably be fine. A point could be made that this should be changed,however, so much here looks really nice.One question-in the future at selling time,is this a home that a larger family would consider because of overall sq footage,neighborhood,schools,etc. If so, I might omit or re-work at least one of the protruding base cabs that run alonside bar stools at the ends...reason: create room so perhaps another stool could be brought up-families[wives] seem to like having the kids there for homework,snacks,small meals,etc.....maximize the potential seating.

In fact,I would seriously sketch up a squarish island-and use another side for some overhang so stools can extend around a curved corner and another side-if you square the island-you could have the wider walkway by frig-and a stool move in along there for times when more people are hanging with you.Adults aren't going to line up in a row as the 3 stools are situated now anyway-it's tight there.
More normal,is people move on and off stools during entertaining-talking with cook then back over to family room,etc. I'd think smaller stools-maybe covered cushions,rotating,and open the whole side of island and around one side for overhang.

consider partially blocking the view onto the fridge, by extending the pantry unit forward (tall cabinet next to the fridge), so that it sticks out and provides a visual break. What I see in your simulation drawings is a bit too much all-can-be-viewed-in-a-glance. When you pull the tall pantry unit forward, you can gain a broom closet space behind it. When you pull the tall pantry unit forward, you partially block the view onto the mud room. A good thing.

if you swap the sink and the DW, you get the advantage of being closer to the dish storage, and you put a clean counter under the window. There will still be plenty of light in the sink, if the sink is near the left hand side. Worry not about symmetry with respect to the window trim, as nothing else in this house is based on pure symmetry. In fact, placing the sink in the middle of the counter there is a sign of ignorance, not symmetry. So, instead of having narrow banks of drawers on either side, do it this way, from left to right: big bank of drawers, sink, DW, corner. Hth.

I would like to see frosted glass fronts in most of the upper cabinets. These cabinets are to show your nice things, not to hide them. When well lit inside, they make everything look good.

The island can look good without the pillars. A wall of stone countertop can be used instead. See Dean_I 's kitchen island. It has so much more space than yours because it is made with 1" sides not pillars. These sides were cut beveled to make them look like furniture not butt-jointed slabs.

Move the prep sink over 18" so as to free up some countertop space when you have to take things out of the fridge.

The prep sink has to be undermounted to match the build quality of the space.

There are thousands of other points that are Right about this space, but I will refrain from congratulating you or mentioning some of them.

Although I would not have put the fridge where you put it, I am considering that this placement spot is non-negotiable at this point in time.

The fridge and the aisle are right sized to let you pull the fridge out completely.

Here is a link that might be useful: Dean_I island