From the front-view photo, there seems to be some abdominal/waist and flank fat that might be useful for contouring, with relatively narrow hip/outer thigh fullness. A side and back view, plus an in-person exam, would be needed to judge buttock projection and donor fat more accurately. A BBL may improve an hourglass shape by combining liposuction of the waist, flanks, lower back, and abdomen with fat transfer to the hips and buttocks. With an inverted-triangle frame, surgery may improve the waist-to-hip ratio, but it cannot fully change shoulder width, pelvic bone shape, or natural anatomy. At 5'6" and 147 lb, you may not need to gain much weight; the better goal is usually a stable, healthy weight with enough donor fat. Gaining too much can make waist contouring harder and may not provide more usable fat. The best plan depends on exam findings, skin quality, how much donor fat is available, and whether hip and buttock fullness can be created safely, using current BBL safety principles and avoiding fat injection into the muscle.