Will just liposuction get me an hourglass shape or do I need a BBL?

You appear to be a good candidate for liposuction and a BBL.Many varieties of liposuction are available including ultrasonic, smart lipo, laser liposuction vaser lipo, power assisted liposuction, and conventional tumescent liposuction. The results depend very little on the method used and very much on the board certified plastic surgeon selected.Liposuction removes fat.  Liposuction may not create a greater problem with skin laxity, but liposuction will not improve the skin quality.  Fat can be taken from many different areas of the body including abdomen, sides, bra rolls, thighs, arms, underarms, flanks, lower back, upper back. You have to consider not only which areas will have perhaps the best fat, but also you have to consider which donor sites will have the fewest problems afterward with the liposuction.  In general, the abdomen and thighs are preferred, but, if those sites are not available, other areas can be used.  Creative liposuction with fat transfer to the hips can make hips appear lifted, and rounder.  If the waist was smaller at one time, the waist can likely be reduced to those same measurements or smaller provided the muscular and fascial integrity has remained the same.The TT will be the only surgery to address abdomen skin laxity in the
appropriate fashion.  With a TT, the stretchmarks to the level of the
belly button are generally removed, sometimes more. The amount of skin
removed in a TT depends upon the surgeon's technique and the patient's
tissue characteristics.  Recommend having the BBL performed before the
TT so that fat harvested from liposuction of the sides, abdomen, and
back can be transferred to the buttocks.

Thanks for the question. 
In this regard, I recommend you waist and back Liposculpture, getting better curves especially in the waist, improving your body contour.
Finally, I suggested take the fat we get and transfer to the buttocks and hips, to mold them and get better volume, contour and butt projection, is that we know as "Brazilian Butt Lift" (BBL).Kind regards

While liposuction will definitely improve the waistline, a fat transfer would be needed to smooth the curve of the hips and fill the hip dips for a more idealized hourglass figure. The only way to know for sure is to book a consultation with a board certified plastic surgeon near you to be examined and see what your options are. Best of luck!