Thanks for your question. Minimizing carbohydrates and relying upon a higher protein diet is almost universally successful. Ideal Protein is a good system that helps with meal replacement but doesn't obligate you to their program forever. It is often a good idea to start a food diary. Literally...
From your photos you appear to be a good candidate for a tummy tuck. This will likely remove your old scar as well as tighten and flatten the tummy. The new scar should be fairly low under the panty line and give you a nice result.
It looks like your muscle have split (diastasis recti) This causes the bowing of your lower abdomen. Tightening the skin and muscles can help to flatten you tummy. It sounds like your surgeon is on the right track. Good luck,DrT