Lining up cabinet boxes in both directions is a little more trying than just lining them up horizontally.

That 5/16" variation at the top is the result of about 1/32" of a deviation out of level on my last box next to the wall.
The simplest fix I could come up with was to glue a piece of veneer between the front of the bottom and middle box. After gluing, paring, sanding, filling, and sanding again, the fix is basically invisible unless you get up close and look for it. With a door above it, it's just not an issue.

The center section is going to be more of a bookcase, with a 2" face frame. The top is a little higher so I can add a piece of trim across the whole unit at a 3mm reveal to the top of the door on either side. The top and bottom are pocket screwed to the sides and the middle shelves are dadoed in. Eventually there will be led tape under the shelf at the front of each.
I cut out the dadoes for the open shelving using my of1400 and a dado jig I put together. Unfortunately, the jig moved a little on the first one, so it chewed up a bit wider dado than what I needed. A lot of cursing happened. Since I didn't have extra plywood and good walnut plywood is a little pricey, I am keeping it and will do a repair. It's on the inside of the open shelves and will mostly be covered by books and other items.
My plan is to do the repair by putting some wax paper over the top of the shelf and then building up minwax 2 part wood filler until just shy of the surface where the dado went askew. I'll then cut out a straight line on the veneer to be repaired and a mating patch. Some glue and tape, sanding, filler, and it should be acceptable.
Today has been all about edge banding the doors for the cabinets. I have 16 doors to edge. I've finally gotten down a good rhythm using a file and sandpaper. Originally I was using a chisel, but that was taking about 4 times longer than the file and the result was about the same.
I've been advised by an Osmo dealer that for walnut, it's a good idea to fill the grain if there is a possibility of water exposure. Since this is in the kitchen, I figure that's probably a sensible move. I'm planning to use timbermate, but I have found the walnut by itself is a bit dark for my purposes. Blending 2 parts white oak to 1 part walnut seems to get me closer to where I want to be. Since walnut tends to lighten up over time, it seems like this might be the smart play.
I was thinking, since I have so many panels to fill and sand back - can I do this with my RO150? Or am I better off just taking the time to do it by hand? I'll obviously be doing some test pieces, but if there are avenues I should just avoid, it's good to know.
Thanks,
Adam