OP, love your ideas for the build. Some of this is a repeat of what others have said.

I would opt for some higher zoot bars, CompCyclist had EA70s not too long ago for $30, but are not gone. I recently got a set of FSA Compact Wings and they are GREAT. Point is, it's not hard to find nicer bars for cheap. Compact bars with slightly flared drops works well on your build.

Unless you are going to pound away your cranks on trails, I would opt for a road triple. It'd be lighter and sleeker. I know gearing is personal, but I'm not a triple person. I find that a wide range cassette and compact cross gearing is suited for any terrain.

Wheels: consider A-23 rims with a higher spoke count. Choose hubs according to how much abuse you want to put your bike through. If you are ok with getting middle of the road hubs, consider Tiagra. Great value. If you want to move into higher zoot, go 105. Go with higher end Deore otherwise.

What about fenders? Velo-Orange has very nice aluminum offerings.

Seatpost - Thomson.