Sounds like a beefy build you got there. I'm sort of thinking.. save the $$ beat the heck out of the stock build and change parts as needed.
You might find that you don't need the extra 12 gears that your scenerio will have.
Is it super hilly where you live?

Also, those Aksium wheelsets appear to be more geared towards road riding and light weight. 20/28 spokes seems sorta weak to be bouncing around trails IMO.

With that said, my build is as follows (it has changed many times...as I'm sure you'll do the same..hence my suggestion to starting stock).
CX mode
cr720 up front/oryx in the back (both have kool stop salmon pads)
campy ergo 9 paired with ultegra rear derailleur
mavic open pro 32h
1x9 build with stock andel crank, eye watcher, outer chain guard
shimano m520 pedals
wtb saddle

summer noodling mode
nitto moustache handlebars/tektro brake levers/cloth tape shellaced
cr720 front/back
ultegra rear d
shimano exacge front derailleur
bar end shifter mounted diacompe silver shifters
marathon tires
fenders
wald front basket mounted on a canti mount rack
brass bell
brooks saddle
mks sylvan pedals (no cages, straps, or anything like that)