Too Thin For Brazilian Butt Lift? What Should I Do? (photos)

Hi... thank you for the question and photos... From your photos, you do have enough fat donor sites for shape improvement on the top of the buttock area. You can have great results due that the bottom area already have a nice shape. 

Congratulations on the birth of your second child. It looks like from the photos that you have really put in the time to get back into shape. Fortunately, you have a good shape to the buttocks and it appears that a BBL will benefit you because of the fat removal from the areas you don't want it and the volume enhancement to where you do want it. Consulting with a qualified plastic surgeon is important because if you wish to have fat removed from the abdomen, an experienced surgeon needs to assess whether the skin will be able to retract enough after fat is removed. Also, it may be necessary to wait longer so that your post-pregnancy hormones have normalized long enough so that your body has stabilized. 

Hello dear!
Thanks for the pictures and provided information as well.
Based on your photos, you are a great candidate for liposuction with a BBL and a tummy tuck with muscle repair, to give you a nice tight tummy and to get rid of the extra skin, and I think you'll get very good results.
Liposuction allows your plastic surgeon to transform your entire shape. You can improve your waist, back and flanks, and of course your buttock, to give you a beautiful heart shape, along with the tummy tuck.
In general, you need to be physically healthy and at a stable weight, have realistic expectations, be a non-smoker and your BMI needs to be 33 or less.
l recommend you to make an appointment with a board certified plastic surgeon to talk about your goals and anything you need to know.
Good luck :)