Is there a limit that Miami doctors can take out and put in for BBL?

Patients interested in BBL often ask questions of the necessary volume for transfer. Ultimately, the answer is two pronged and based upon both patient expectations and the nature of fat graft themselves.
BBL and fat transfer is ultimately dependent upon the long term viability of the fat grafted. That being said the resorption rates of fat transferred can be significant. Clinically this translates to a progressive loss of grafted volume in the months following the procedure.
I tell patients that they can expect resorption or graft loss on the order of 50% (on the high side). Additionally some harvest volume is lost in processing the fat graft prior to transfer. Thus I generally recommend that patients seeking even the most minimal volume increase have adequate reserves for grafting of 500 cc per cheek (at minimum).  This means that harvest will usually exceed 1 liter (assuming for processing loss).
However, it important to remember that these are recommendations and can be amended based upon a patient's particular expectations. Some patients only want a subtle change and may be willing to accept a less significant result. But the rule still applies you have to have the fat to transfer the fat.
With regards to your specific question, the generally accepted limits for liposuction performed in the office setting is 5 liters. This will vary, somewhat, from state to state (Florida limit is 4 liters). There are no limits for procedures performed in hospital setting. In general, there is always greater risk associated with large volume liposuction. Patients often disregard the medical consequences of large volume liposuction including the massive fluid shifts which can occur.I typically tell my patients to prepare for a 50% resorption rate (at worst). This combined with processing losses means that I will typically suggest that for a slight increase they will need a harvest upwards of 1 liter (500cc per cheek which may potentially decrease by 50% per cheek). More significant results will necessitate several liters harvest.Often times for patients without adequate reserves, the way in which to approach the procedure is primarily for the contouring benefits of circumferential trunk liposuction. Any donor fat obtained will be processed and grafted. Any volume retained (no matter how minimal) will then be viewed as an added bonus rather than an underwhelming primary outcome.
It is difficult to make any reliable volume predictions based on photos alone. That being said, your photos suggest you are a reasonable candidate for surgery. I would, however, caution against unrealistic expectations. 
As always, discuss your concerns with a board certified plastic surgeon (ABPS).

It is hard to impose a limit on the amount of fat used during BBL surgery because each patient has a different set of anatomy.  Take note that a prudent surgeon will not over-inject the buttocks to the point that the fascia system is destroyed, leading to disaster--sagging appearance, dents and cellulites, and less than optimal shape. The fascia system holds the skin and the entire shape of the buttocks.  Hence, the fat volume should not be too heavy or too excessive to the point that the supporting structures are weakened. 

In body contouring surgery, bigger is not always better.  First and foremost, we must respect the starting anatomy of the patients to prevent complications that may appear right after surgery or years down the road. 

Good luck and best wishes.