Something like this... Move the cleanup sink and DW off the island Move the range toward the refrigerator Add a prep sink to the island Add a trash pullout in the island situated so it's easily accessible from the Prep Zone, Cooking Zone, and Cleanup Zone. Four seats at the island With the addition of a prep sink in the island (24" sink base cabinet), your primary Prep Zone is in the island...you can visit with family & friends while prepping. You also have a secondary Prep Zone b/w the range and cleanup sink. The Prep & Cooking Zones are separated from the Cleanup Zone and no tripping over an open DW door! With the Cleanup Zone (sink + DW) out of the island, the dirty dishes are no longer in the way of prepping and are no longer front & center on the focal point in the kitchen...the island! The sink/range counters are 30" deep. If it's in the budget & available in your cabinet line, I would get deeper base cabinets...28" would be ideal. If deeper base cabinets are not in the budget (or not available), standard depth base cabinets (24") can be pulled out from the wall 4.5" or so. Because the refrigerator doors must extend past the counters to open fully, the small run of counter to the right of the refrigerator is the standard depth of 25.5". The upper cabinets are all 15" deep. Since you have an abundance of counter space, you could even afford to lose some to an appliance garage in the corner. 55" is still a wide aisle, but hopefully with the prep sink in the island as well as the cleanup sink only 4' away from the range, the aisle won't be too bad. On the plus side, you can have someone cleaning up, someone prepping at the island, someone prepping b/w the range and cleanup sink, and someone cooking...all at the same time with no one bumping into any one else. You could even have someone making a snack without getting underfoot. (this assumes the pantry & garage door cannot be moved, keeping the columns, and keeping your basic layout) Be sure, though, that if you go with this deep an island that you can reach across it to clean it. Can you reach at least 33"?

I'm sorry to say but your kitchen layout could be much better in terms of function. Right now your island is a barrier. And as mentioned, that corner oven divides your counter space. Best kitchen function is when you work from fridge, to sink to prep to cooking without having barriers between those functions. Right now the way that kitchen is set up, whoever is the cook will be doing a heck of a lot of running back and forth and crossing zones. I would seriously suggest you read up here on the forum on kitchen design and function. Lots of excellent threadsHERE.

With the beveled corners, drywall is, by far, your easiest option. But for the corners, I would suggest a lap & gap siding (if you can find it in a non rough sawn finish). But even that is probably too much given that the butcher block top doesn't have square corners. And, because the kitchen is small, I would paint it the same color as the cabinets. Going to be dark in there but you can amp up your lighting...maybe lighting in the features shelving and thin LED strips or LED tape lights under the counter edge? And maybe some light colored runners for the floor>

You need pendants with chain. and EXTRA chain and wire. Or the fixture must come with a pivot and the ability for additional stem or customization on the light order.. . It would help to know the highest ceiling elevation. A 126 inch island is not HUGE. You need nothing close to an 82 inch single fixture. It will take OVER : ) Three pendants, forcing light down onto the counter would be just fine. No wider than 15 inches if three and no more than 18 to 20 if two. . You can augment with recessed as well.