I want a more defined jawline - Do I need a neck lift, lower face lift, or just chin lipo?

Based off your photos - you could benefit from some chin liposuction and J plasma or some type of RFA treatment invasively to help with the skin. (I would do this and then see how you heal and if you are content no neck lift needed) Neck lift would be next option but that is also scarring behind the ear that your surgeon would discuss with you and this would ideally give you the most pull in your next to define your jaw line. As far as buccal fat removal goes - that will help slim your cheek and not address the jawline much. A mid face lift (helps with some of the jowling) and some fat rejuvenation to your malar region would help with some of the facial descent you are experiencing and also will address some of the jawline as well.

Anatomically, all necks are not created equally. That said, for you to get definition and a more acute neck angle, you would benefit from a deep plane neck lift which addresses the fat, muscles and submandibular glands beneath the skin and superficial fat. This combined with a small chin implant or fat grafting to the chin and mandibular border would make a huge difference. Buyer beware… liposuction with skin tightening will only give you modest improvement at best.

Based on these photos and short of in person evaluation, my suggestion would be an anterior neck lift with neck liposuction. In-person or teleconference consultation with a board certified plastic surgeon with expertise in neck lifts is recommended. Good luck.