I'll critique your build

Frame- Soma Saga (Can’t get a deal on LHT right now or it would be in the mix) - good choice
Rims- Mavic A719 or Velocity Dyad 36H - go for the A319, they are cheap and strong. I have seen many A719's crack at the nipple hole.
Hubs- XT - Go for a cheap sealed bearing hub like a formula
RD- XT - find a used one on ebay - the old ones are great
Cassette- Deore something, 9spd (Low range, not sure which yet) - I would choose a wide range like an 11-34
FD- Not sure it matters that much, maybe a 105 or SLX or lower. - doesn't matter, get what ever you can find
Headset- Cane Creek S3
Stem- ? - try a bunch and make sure you get the right fit (the most important on a tourer imo)
Bars- Want drop bars, Nitto Randos seem to be the big hit.
Seatpost- ?
Saddle- Not that important right now, but am thinking about finally trying a B-17 - great saddle, but make sure to allow enough time to break in
Tires- Vittoria Randonneur 700x35c
Shifters- Barcons, probably Shimano DA - I personally like old 9spd shimano STi's - I have ultegra on mine and love em
Crankset- Kinda open on this one, am thinking an MTB would be more appropriate for my purposes, maybe an SLX although Sugino DX600 is appealing.
Brakes- Not sure yet, Paul’s seem to be the best canti choice but I’m open to suggestions.
BB- Depends on the crank.