Lie Angle

You are on the right track. Here's a couple more things you might want to do, working with a good fitter:

• Put impact tape on the bottom of your 5, 7 and 9 irons. Hit a half-dozen shots with all three. See if the 3/8" scuff mark is in the same place on all the irons. If the 5i and 9i are pretty much in the middle, and 7i is 3/8" off, that means the 7i may be out of tolerance. Don't automatically bend all your irons because one has too flat a lie.
• If the iron lies are off, you may need some combination of lie angle and shaft length adjustment. A skilled fitter can help you on this.
• A couple of different companies make the sole tape; make sure you have it in the proper place on the sole, and make sure you know how to interpret the left/right deviations.

As for which irons are bendable, I would contact Callaway on this. The hardness of the steel and the shape of the hosel (some clubs don't fit into a bending tool very well without getting damage) influence how bendable a club is. OEMs often recommend a factory lie adjustment if the clubhead metal is brittle, or has an odd hosel design.

Why adjust lie angle? Conventional wisdom says that lie angle is pretty steady for an experienced golfer. If lie angle is too flat, you tend to miss to the right because that's where the club is pointing. Too upright, miss left. Several different club fitters have told me that lie adjustment is one of the biggest - and simplest - benefits of more customized clubs of the past few years. If you have a consistent swing (12 HDCP looks pretty good to me), it's easier to tweak the clubs than to jack around with your swing.