I don't think the high BB is related to the rear end of the bike, but more to do with the tubes of the front triangle and stuff. I'm running plenty of sag.Nice ride report socket.
Funny thing is that when you first posted the pics I thought to myself the head angle looked kinda steep for 64 deg. Figured it was just the photo...never easy to judge HA from a photo. See if you can get an actual measurement. I printed off a 90 degree increment protractor I found on the net and then use a plumb line to find absolute vertical and measure it that way. Still is not dead accurate, but probably good to +/- 1/2 deg.
I reckon the high BB may not only be making your HA steeper, but also influencing chain stretch because the virtual pivot (IC) will be higher up if the suspension is sitting higher. Try that 38T!
Sounds like that 9.25 shock might be just the thing, although that will probably put your BB around 13 7/8.
I'm pretty keen to try the shortened shock idea, gotta call Cane Creek and see what they say. It's going to mean I have to reinstall the shock again though which I'm not looking forward to
Zero Knowledge: you're right, assuming the change in sag doesn't affect things too much (but on this bike it does reduce the anti-squat quite a bit), but the difference in anti-squat due to the changing angle of the bike could not, in my estimation, be big enough to make that particular difference. I think realistically the main reason I don't notice it on the trail is cos I'm paying attention to other things, like not hitting trees, and the suspension is actually being worked