Will I permanently lose flexibility after tummy tuck? (photos)

OMG, I didn't realize the human body was that flexible!  What a great question. 
I personally have never run into this situation with such flexibility along with a surgery that, if done correctly, gives a great deal of tightness both of muscle and skin.  It would seem to me that your flexibility comes from both your vertebrae, your ribs, and probably other bony and muscle interactions such as hips.  I don't understand your area but I certainly do mine.
In a well done abdominoplasty, the correction of the rectus diastasis is done with suture that is replaced by scar tissue within 3 months.  Once this scar tissue has matured, it may not be quite as pliable and distendable as the muscle itself.  Also, the skin of the abdomen is normally connected to the skin of the anterior thigh and the remnant of the mons pubis by scar which acts as an anchor to hold the anterior thigh skin up and the abdominal skin pulled in a downward direction.  
Certainly, you understand that skin stretches since you had one or more pregnancies, and your abdominal skin adapted to the forces placed on it by the uterus by stretching out.  Muscles also adapt to forces placed on them.  Therefore, I believe your abdominoplasty, if given sufficient time to heal and mature, should allow you to regain most if not all of your flexibility since the flexibility actually came from the skeletal connections and not soft tissue.  
Obviously, I am way out on a limb here but I believe the same determination that allowed you to be such an incredibly flexible person, along with the skill and experience of your Board Certified plastic surgeon working together after surgery and during your recovery and post recovery periods should allow you to regain almost all, if not all, of your flexibility and having a great looking abdomen to boot.

Dear cflask,
you shouldn't be worried about skin flexibility. Even after tummy tuck your skin will adapt and it will regain its flexibility. However, you should go slow and avoid overstretching in early stages of recovery.  
I hope this was helpful,
Dr. Barrett,Beverly Hills, CA

That would probably be impossible to answer as scar is generally restrictive but becomes more mobile with time and activity.