Had panniculectomy and lipo in flanks. Should I have more lipo or complete TT by tightening my abdominal walls? (Photos)

It depends on how lax the abdominal tissue is...from the umbilicus to the bikini line. If there is sufficient tissue, the full abdominoplasty will remove the excess skin/fat of the abdomen (from the belly button to pubis). It will also tighten the vertical abdominal muscles (rectus) and also the oblique muscles to help cinch the waist.
The result will be a contoured, tighter abdomen...the tighter muscles will also help with the low back pain due to the lax anterior abdominal wall. Good luck!

Based on your photos and current weight, it would appear that a tummy tuck should be delayed due to the presence of significant intra-abdominal fat.  The panniculectomy has taken care of the distressing lower abdominal skin and fat excess, but for the cosmetic part, a tummy tuck, best results are obtained when the intra-abdominal fat is much reduced.  You could do that in consultation with your plastic surgeon and a medical weight loss practice to determine the time for the tummy tuck.

Based on your photos, it appears you have significant intra-abdominal fat in addition to extra-abdominal fat. For you to have ideal results, the best first step is not surgery. It is weight loss. I say this because lipo and/or tummy tuck only addresses fat that is between the skin and muscles, and does not get rid of your intra-abdominal fat (the fat around your organs), so the result you could get is limited. When there is a lot of intra-abdominal fat, neither lipo nor tummy tuck is going to give as good of a result as you may be hoping for. To get a nice flat stomach contour, part of the work has to be done on your part to reduce your weight. Once you are able to reduce and maintain a stable weight,  a tummy tuck would help contour the abdomen and tighten it, and can be done using the same lower abdominal incision. Lipo may also be helpful, especially along the sides, or flanks. The reason I do not recommend lipo right now, is that you need to already have a good diet and exercise plan in place, or else the results created by the lipo won't last. If you consume the same number of calories you are now, they have to go somewhere, so the fat that was not liposuctioned will grow in size, and the shape created with lipo will not stay. [It's hard to figure out the other parts of your question. What is the 8000? A price, as in $8000? Is this a quote you have been given, or are you asking if what you want can be done for $8000?]