How common is white line levator dehiscence? Including locating the elevator, mobilizing orbital fat, and anchor blepharoplasty.

Please understand that having a photograph posted on realself is not a substitute for an actual personal consultation.  Also please understand that the work you need is generally not available even from otherwise qualified oculoplastic surgeon.  These are very specialized skills.  If you decide to have surgery and actual see surgeons in consultation, you need to carefully evalutate their examination and what they are telling you to come to a decision if they are remotely capable of delivering what you need.  Take your time in deciding which surgeon to work with. 

This explanation is an exellent one of external levator ptosis repair. Did your surgeon also describe other techniques available to treat ptosis, such as internal ptosis repair with conjunctivamullerectomy? These two techniques are the most commonly used procedures to treat eyelid ptosis, and each has its benefits and downsides.For example the internal approach is minimally invasive with no need for a skin incision which makes the recovery quicker. It is often more predicable in cases of mild to moderate ptosis. External ptosis repair is excellent for moderate to severe ptosis, but can be a bit more unpredictable with slightly higher revision rates. You may be a good candidate for either of these procedures, and as long as your surgeon is facile in both procedures, he or she can work with you to choose which one is the right option for you. 

This sounds like they gave  you a very complete explanation of what you need done.  In ptosis the levator muscle is stretched so it needs to be tightened and attached to the tarsus.  If you are hollow, repositioning of the medial fat pad instead of removing it can help to fill in the upper sulcus.  Not may surgeons do this so whomever you saw is up to date on new techniques.  Many of us like to do the anchor blepharoplasty as well to help make a nice crease and support the lashes.  So sounds like you went to someone who would do a good job.