I had cheek and jaw implants removed in November, but now I have laxity and visible scar tissue.

Thank you for the picture. I do see some volume loss in the cheek area and skin excess in the lower face. I am not clear as to the scar tissue you are referring to, and that is something that can be examined during a physician examination. You are right, you would do great with volume enhancement with facial fat grafting and some type of facelift- such as a mini lift or a lower facelift. This combination of procedures would greatly address your concerns with natural results!. 

I would counsel you away from grafted fat-it is like injecting scar tissue.  The face has many glide planes and these fat grafts scar these delicate planes.  I do not believe that your photographs are adequate for assessing what you need.  I suspect you would benefit from a vertical mid face lift over a hand carved orbital rim implant.  If you are open to it, hyaluronic acid fillers are also an option but you need to find a surgeon who is an artist with these treatments.  The only fillers for this purpose are Restylane and Restylane Lyft. Other hyaluronic acid fillers are too runny to work for you. Specifically avoid fillers like Juvederm, Voluma, Restylane Silk, and Belotero.

Since your implants were removed in November, whatever scar tissue that is there may improve somewhat over time.  That said, you certainly could be a candidate for a face lift with fat grafting for the volume loss. As an alternative, you also may benefit from fillers such as Voluma and a less invasive procedure such as Thermi , Ulthera, etc (albeit with not as good a result as surgery).  Best wishes.