mm718 had mostly great suggestions as did a bunch of others.

I would skip body powder and get Body Glide or Chamois Glide that stuff works very well and is easy to put on. I would go with a scented deodorant. Kiss My Face makes an active one that doesn't smell bad and could help mask some sweat odors though killing the bacteria is the best way to do that.

Sports drinks are mostly silly go with Camelbak Elixir which has no sugar and more electrolytes and vitamins than most others (at least of the several that my former boss tested last year). The Camelbak podium chill bottles don't hold onto flavors well so they can be rinsed and used again easily.

Baby wipes are extremely useful and I highly recommend carrying them. The Seventh Generation ones are my go to as they are generally free of crap (well until you wipe down there).

Boxers should pretty much always be ExOfficio (nearly all mine are and most of the folks I have worked with have a pair or three). They are perfect for travel and you really only need two pairs and if you have cycling shorts you could get away with one and wash it and dry it while riding and wear them at night. The new sport mesh ones are a bit lighter and I would take two anyways just to have them.

The Surly rack is well built, looks nice, works great but heavy I would switch it out for a Tubus Cargo Evo or Logo Evo rack and go with the Tubus Duo at the front. That combo is solid if you can rock it and weighs less combined then just the single Surly rack.

Curious if you are a Wob or just a general anarcho-syndicalist or just like red and black?