It makes more sense that the "REF" next to the sink is mislabeled and should really be "DW".

What else are you planning for the Great Room - side/coffee tables? TV? Other items?

There will need to be room for not just the furniture but also easy circulation around the furniture.

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The Refrigerator next to the Pantry is very far from the Prep Zone b/w the sink and range.

Will there be seating at the island? If so, then the island as drawn is not likely very functional storage-wise. Full-depth base cabinets/drawer bases under the seating overhang (if there is one), will be very difficult to access. Stick to no more than 15" deep cabinets or so.

Regarding seating overhang - if you plan seating, the minimum recommended is 15" of clear leg/knee space. If your family is tall or has long legs, more might be better. Additionally, if there will be back-to-back seating at the island and a table in the Nook, aim for 60" b/w the table and the island overhang.

If no seating is planned at the island, then back-to-back full-depth base cabs/drawer bases in the island will work. In that case, the island's depth would be 4'3", not 4'6" (1.5" counter overhang in the front of the island + 24"D cabs/drawer bases + 24" cabs/drawer bases + 1.5" counter overhang on the back of the island = 51" = 4'3").

And, if no seating at the island, then 54" or so is all that will be needed b/w the table in the Nook and the counter overhang.

Regarding the aisle b/w the island and a table in the Nook - since that appears to be the primary (and maybe only) access to the what I think is the backyard (top of the layout), that has the potential to be a busy aisle, so 54" if no island seating and 60" if island seating becomes important.

For the table in the Nook, there should be at least 36" b/w the table and the walls for room to have seating b/w the wall and table.

I never like a trip past the range to get from fridge to sink. So much better if you name all the spaces.next to the doorways we see.. Is the mud room at the front door ? Since you do not give us every measurement clearly marked some things I can only guess . Yes of course you need the DW by the sink. How many seats on a regular basis for the great room ? Is there another space for entertaining or just the great room. For me too much missing info.I am tll and have found a 12" overhang on an island just fine but I think you have space for a larger one.