I'm building a cabinet just as you describe: in a corner between two windows (one side of the corner is wider, so the cabinet will be 30" wide and 12" deep). The purpose is to hide the tangle of coffee grinder, electric kettle, and infrequently-used espresso maker (main coffee maker will be out in full view). Coffee is important to me but so is an uncluttered countertop. There are several types of doors you can use: 1) A single door that lifts up and out. This doesn't allow access to the upper part of the cabinet when open. 2) "Flipper" doors that fold to the sides and then get tucked inside the cabinet sides. These require at least 2" extra inches on each side. 3) A barrister-style door that lifts up and slides into the top part of the opening. If the opening is much taller than it is deep, it will stick out quite a bit when open (so not really tucked away). 4) Tambour door (rolltype style). I have never been a big fan of this style, but for my application - opening that is 20" tall x 27" wide in a 12" deep cabinet - I decided it's the most functional because it allows easy access to the inside and the door doesn't block anything else when it's open. But these range from hard-to-use and short-lived to lifetime doors, depending on how they're constructed and maintained. As with anything, the devil is in the details, and price and quality are positively related.

Seeing the side of the fridge wouldn't be ideal, but you could have the fridge integrated in to the cabinet design rather than having an awkward wall. And I think if the soffit stays, the wall should stay within the confines of the soffit, rather than being 4" proud like the picture.Just had another thought, if you didn't wan't to do the cabinet integration idea, you could notch out the stub wall top plate, and a couple studs in the back wall and inset a steel L bracket to give the top of the stub wall more strength.

What great timing! I just finished the caulking and now it just needs one last coat of paint on the casing (door trim). We had the countertop cut so it extended all the way to the wall and notched the casing around it. It looks totally fine IMO and I don’t even notice it :)

In terms of overall length, I have from left to right: 48" Freezer(18")/Fridge(30") 3/4 inch side cover panel 120" counter top, therein 36" induction cook top 3/4 inch side cover panel 30" wall ovens 48" pantry (2x24" high cabinets) 2" cover panel to the wall = 249.5" Total I've been going back and forth on the hood. It's probably the most discussed item. Originally we planned to get a custom hood liner built for an insert hood, but now we are leaning towards this very basic BOSCH pull out hood. Minimum mounting clearance over cooktop is 25 3/5". There is no maximum clearance given in the spec sheets. It should come in right around 30-32" clearance (math: 84" tall cab (incl. toe kick) - 36" base cabinets - 15" wall cab to mount the hood to - 2" for the hood hardware = 31"), which is very average as far as I can tell. I was planning to build a custom open cabinet left and right of the hood cabinet which will probably be around 16-17" high to seamlessly integrate the pull-out. See inspiration below.