No USB charger on the dynohub? If you have the dynohub, the charger is not a big addition.
Battery taillight, if you have a large seat bag the light can be blocked. Suggest seatstay mount for battery taillight, or one that you can instead put on a rack if you occasionally use a rear rack.
For a coupled bike, would you be happier with plastic fenders that are easily replaced instead of custom painting fenders to match the frame? And make sure you can fit it in the case. I can't fit my fenders in the case with my S&S bike, fenders stay home.
I put a fender mounted dyno powered taillight on my Lynskey, but that is not a coupled bike. I do not use dyno powererd taillights on a coupled bike, the wiring is more than I want to deal with when I pack or unpack the bike. Plus, I often use a blinking taillight in daytime, so I consider my battery taillight(s) to be my primary light and the dyno taillight to be my secondary taillight.
Are you really sure you need hydraulic brakes with a coupled bike?
Pump mount, see rule 30 (I readily admit that I often violate this rule myself):
https://www.velominati.com/the-rules...pumps-rule-30/
For low gearing, you will need a total wide range of gearing or you might spin out on the downhills. Thus, unless you want a huge cassette, get a triple. I have pretty good gearing with a road triple and an 11/32 cassette.
Handlebar bag, you did not mention how you mount it. But if you have a fork crown mounted headlight, that suggests not on a front rack. That said, get any fork mounts that you might need later if you wanted to put a front rack on. I use a second stem, not a front rack for my handlebar bags. Some time back I described my second stem setups on some of my bikes, photos here:
https://www.bikeforums.net/19930025-post28.html