I have a question.  If I have a rog/ftr/mnk, and I go mechanic for Gxbow will that satisfy the Ftr kensei crossbow enhancement to allow my character to stay centered when i take monk levels?
*specifically can I save the exotic weapons Feat slot, or do I have to take the feat for kensei to count?*

Icon Enhancement Crossbow Training.png Kensei Focus: Crossbows: You focus your Kensei training in the use of crossbows. You gain +1 to hit with heavy crossbows, and light crossbows. (The Exotic Weapon Mastery enhancement will add great crossbows and repeating crossbows to this list of weapons.)  Am I interpreting that incorrectly?
*      Arbalester: Your ranged sneak attack and Point Blank Shot range increases by 5 meters per trained Mechanic Core enhancement. You also gain proficiency with great crossbows.*

That enhancement makes the crossbow a kensei focus weapon.  It doesn't make it a MELEE kensei focus weapon, i think is the issue.

The only ranged weapons you can be centered (Ki Weapons) with are shuri, natively, and bows (using zen archery).

Sounds like you could easily test with an iconic throwdown