I am building this bike with SRAM XX Reba fork, XX crankset and Easton Haven carbon cockpit. Here are my questions:

1) Are the 1.5" tapered head tube bearing races built-in? What brands do you recommend?
2) What is the ideal Q-Factor of the BB95 bottom bracket....156 or 168? The frame is a small(15.5) - so the XX crankset will be a 170mm.
3) Frame is shipped with Rock Shox Monarch 3.3 rear shock. Is the rear travel 110 or 100? Is this shock the same level as the Fox RP23?
4) Can I convert the rear BACK to 135x10 QR spacing if need be?

Your insight is appreciated. TIA....