Wow a whole bunch of follow-ups.
On the dishwasher front, I don't think we'd see much use of it in the brewery. I actually don't find us dirtying too many items that would actually fit in a standard dishwasher. All of our fermenters are 13gallons, kettles are 15g, and we only usually dirty the mash paddle and grain scoop which take only a few seconds to clean up. Hoses are generally utilized in a way that clear water is the LAST thing to pass through them so they wouldn't go in.
On the topic of kettle size, I would get 20g kettles to facilitate 2 things:
1) Less attention during boil (15g I usually have only an inch from the rim making boilovers a real possibility). Usually we start the boil with 13.5g-14g of wort!
2) Being able to hold more mash/sparge water. With 15g, I have to re-fill the HLT with an additional 5 gal of water after mashing in which slows the herms rebound time to mash temps.
I actually seriously considered adding a plenum, but the HLT and MASH Kettles produce 0 steam under normal circumstances so I don't actually run the fan during most of the process. At the end, when I boil for about 60 minutes, the bk is located right under the intake for the fan and the hood works pretty well. Realistically, your Range Hood should work fine as long as the fan can pull enough CFM to keep up with boil off steam.
I did look at attaching a drainboard afterward, but they didn't look as sturdy and I figured I could fashion something myself. So far, I've been too lazy to do that.
You're definitely right on the 2 degree differential, I have no complaints there. I figured when these hoses are ready for replacing I'll go ahead and upgrade to the thicker material. If you're just getting started, I'd jump to the thicker stuff right off the bat. Not only is it more thermally insulated, it won't kink as easily when running hoses to your pumps!
Generally speaking, having the kegerator in the basement was a decision in hopes that I'd finish the adjacent part of the basement into a man-cave/bar space. Again, I haven't started that yet, but I don't mind walking down stairs to grab a glass.