Stretch your hip flexors!
I'm just putting this out there in case there are other ladies like me who don't have access to a PT and are dealing with a postpartum belly that seems to be forever looking pregnant.
When you are ready to return to exercise, in addition to whatever you're doing for your core, make sure you're stretching your hip flexors, glutes, chest, and all the muscles that were helping support your baby belly for nine months. Hip flexors specifically become short and tight during pregnancy and will tilt your pelvis forward, leading to that "could she still be pregnant?" look.
I'm just over a year postpartum, regularly working out and (trying my best!) to eat right and nothing was working until someone pointed me towards stretching my hip flexors etc. While it's done nothing for my weight or where I'm carrying it, just two weeks of daily ten minutes stretching sessions has got me a) no longer looking like I might be pregnant, b) fitting back into some of my pre-pregnancy jeans and c) feeling better about my body for the first time in a long time.