Is It Possible to Have Fat Transfer on Hips and Outer Thighs?

You should look into the Brazilian Buttocks Lift. This is essentially what you are describing. It takes fat from prominent areas and transfers it to the buttocks to improve fullness and projection.
This typically requires large volumes of fat.

Thank you for your question.Yes, it is possible to have those procedure at the same time. But first, for safety reasons, to be a good candidate for the procedures you want at the same time, your labs and  cardiovascular preoperative evaluation must be optimal.
Kind Regards,Dr. Emmanuel Mallol Cotes.-

A good candidate has enough fat available for transfer in the procedure. The amount of fat that can be transferred in a BBL depends on how much fat the patient has to harvest and the amount of space there is to move the fat into. It is recommended for the patient to have a BMI of 30 or less. If you are too thin, a Brazilian Butt Lift may not be possible.

Hello dear!!
Thanks for the question and provided information as well. 
Yes, it is possible, but unfortunately, without pictures, it is very difficult to give you a proper answer. 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 :)

Fat transfer to the buttocks is currently regarded as the work horse for buttock augmentation. The transplanted graft survival is technique dependent but in general is high. Transfer of fat to other areas could be performed as long as it is placed deep enough to avoid surface irregularities. The amount of transferred fat is dependent on the amount available for liposuction. As a general rule the transplanted fat graft is around 30% of the amount liposuctioned. Hope that helps!