First and foremost, I recommend that you go to a board-certified plastic surgeon to have all these areas evaluated. Generally, as an outpatient surgery, we want to limit our surgeries to 5-6 hours maximum time, and all the procedures you had mentioned would take more than that amount of time. I would say either break it up into a couple of procedures or have it done not as an outpatient surgery but in the hospital. Secondly, I don’t recommend doing a BBL and Tummy Tuck at the same time especially if you want a large amount of fat placed and if you really want a large buttock from the procedure. Because laying on the buttock as is needed for after tummy tuck will comprise the effect of your BBL. So a good option would be to get the lipo and BBL done first. After several months you can finish off with a tummy tuck and thigh lift.
You will get the best answer to your question by scheduling an in person consultation with a plastic surgeon certified by the American Board of Plastic Surgery and discussing your unique situation and concerns. The surgeon would meet with you and examine you, physically feeling the tissue, assessing your desired outcome, taking a full medical history, and discussing the pros and cons of each operative procedure in person and what you can realistically expect. Then you can make an informed decision on which procedure(s) to start with according to your desires, recovery time necessary, your history and current health. One of the most important factors is not only your health going into the procedure(s) but the support system you have available for your recovery time and the amount of time you can seriously devote to recovery. If you have active children and only a few days where you can rely on assistance driving, taking care of housework and children and daily activities then staging the procedures may be your best option. If you have help for a good two weeks where you can really focus on you and your recovery and someone else is going to take care of the daily routine and responsibilities than it is not uncommon to do combined procedures for one surgery, one recovery. Patients that have the needed recovery time scheduled in advance usually recover faster as they don't have the added stress of knowing they are needed only a few days after a tummy tuck to be back to their normal routine. Take all of this into consideration with your surgeon when making this decision and get realistic answers to your concerns in advance will make the whole process easier. BBL is often done as a separate procedure ahead of the tummy tuck and thigh lift, as this may optimize the amount of fat retrieved, allow for some skin retraction and the ability to touch it up at the time of the tummy tuck. It also allows a more aggressive skin removal in the tummy tuck and thigh. Any combination surgery should be done in about 6 hours or less in order to optimize safety in surgery, including lower risks of blood clots and cardiovascular complications of anesthesia.