What would give me the best bang for the buck to give me a lower facelift, fix saggy jowels and a nice jaw contour? (PHOTOS)

Your photos demonstrate jowls and a heavy neck. In this situation a facelift and neck lift combined with submental liposuction would provide the best approach in the long term. Thread lifts also are targeting a lift on the skin and hence do not last long since there is no lifting and repositioning of the deeper layers and no tightening of the muscle. A mini-facelift also will not adequately address the neck . Have a look at the before and afters in the link bel,ow to get an idea of what can be achieved. Good luck

Based on your photos and stated desire for long-lasting improved facial and neck contour.  You would benefit most from a standard cheek and necklift, essentially a facelift.  This would allow appropriate fat removal under the chin, along the jawline and perhaps in the lower jowl region, platysma muscle tightening  in the neck and suspension of deeper soft tissue in the face.  The end result would be a more youthful shaped face with a more defined jawline, neckline, and smoother cheeks. With all of these changes, I strive for a natural appearance.

based on photos you need a neck/face lift and co2 laser resurfacing. without surgery you would get improvement with at home peels like cosmelan (see link), starting skincare, lasers like co2 or halo + bbl. and morpheus and threads for lifting. you really will need a combination of treatments. 
With significant neck sagging you would need a neck/face lift with muscle tightening (platysmaplasty). at the same time lasers (fraxel,  co2 or erbium( or microneedling RF (fractora, intensif) can be . performed to improve the crepe skin or wrinkles.  You need a formal consultation, as the neck can be treated with a combination approach:
1. micro needling and lasers for texture
2. botox, disport or xeomin to help platysmal bands
3. intensif or fractora RF microneedling for crepe skin and lifting
4. fillers like belotero, restylane silk, juvederm volbella to improve lines and folds
5. neck/face lifting if sagging is prominent or early starting +/- platysmaplasty (muscle tightening)
6. J plasma/Renuvion, thermiRF, inmode facetite for internal tightening
7. ultherapy and thermage for external tightening
8. regular Venus legacy, exilis ultra, or inmode forma treatments with facials to maintain tightness
9. PDO novathreads or silhouette instalift cone threads for lifting and long-term collagen production
see an expert for a full evaluation and treatment plan based on your individual situation and goals.
Best, Dr. Emer.