If they have not started the wheel build yet, you might consider a CSS rim. Costs a bit more but will last forever. The brake pads also cost a bit more, needs special pads. If you are using your bike for your sole transportation, a rim that lasts forever may be one of those things that interest you.
I do not know if you need a different bottom bracket for a different chainline. You might want to ask SJS if the one you have is good enough.
Sounds like you ordered the variety of hub that I would have ordered if I tried to put one on my Sherpa. I probably would have preferred mounting the cable stops to the cantilever post. Not sure what they have for clips to hold the cables to the toptube, but I am sure that you and SJS will figure something out.
There recently was a long thread on re-using the filler cap. You will not need to know about that for a while, but eventually you will need to know how to do an oil change. I re-used my filler cap this past weekend, but I put new coat of blue locktite on it before putting it back into the hub. I over the years bought two oil change kits (complete with syringe, spare filler cap, hose) so I have a couple spare filler caps if one gets lost.
There are at least three different theories on how much oil is needed in each oil change, I use 15 ml. Rohloff specification is 25 ml. Thorn has suggested a couple numbers, one of which was 15 ml.
It will be noisy in gears 1-7 at first, but after the first oil change it gets better.
You are going to like it.