Thank you for your story and questions.
Nothing substitutes for a personal evaluation and a face to face discussion of your options. Unfortunately without a examination I can advise you in general terms, however I hope you will find them helpful.
The simple answer is YES attain your goal weight first and the reasons are:
1) your goal weight attainment is very important for not only your final result but your overall appearance.
2)you didn't mention your height or current weight. Body Mass Index (BMI). A BMI over 30 and greater is associated with progressive increased complications.
3) In most people your face (and other parts of your body) often will change size with weighit fluctuations. Thus, if you loose weight after surgery your underlying normal fat deposits may change resulting in the potential "loosening" of the skin.
5) modern face lifts usually our a combination of surgically tightening the underlying structures, adding fat where needed and judiciously resecting redundant skin where needed. Thus, alterations at the time of surgery are based on the "here and now" and not on "what if" since all individuals change differently with weight fluctuations.
I suggest you make out a list of your questions and select several "model" photos of what your desired goals/look would be and then schedule several different consultative appointments with experienced Plastic Surgeons who are Certified by the American Board of Plastic Surgery and who are ideally members of the American Society for Aesthetic Plastic Surgery (denoting by membership as having met additional criteria and a focus on Cosmetic Plastic Surgery).
R. A. Hardesty, MD, FACS
Diplomate and Certified by the American Board of Plastic Surgery
Awardee: Real Self Top 100
4646 Brockton Ave
Riverside, Ca 92506