Great job!! His condition is improving rapidly. It's nice to see the tail base getting chubbier, he's getting some of his nutrient reserves back already.
I'd hold off on the pinkies though. A beardie who has been starved usually has some digestion issues and its body has a tough time breaking down large chunks of animal protein and fat at a time. Rescue beardies who are fed pinkies have a much higher rate of fatty liver disease because of this than the rest of the bearded dragon population. Pinkies are a pretty common source of liver disease even in otherwise healthy dragons.
If you are lucky enough to get him to eat his greens, aim for about 50% salad and 50% gutloaded insects like crix, silkworms, butterworms and the occasional superworm. Some watered down chicken baby food smeared on the greens might convince a reluctant salad eater if needed.
I'd push as much water as I could get him to drink as well. Those sunken fat pads show significant dehydration. Flavor it with a little white grape or apple juice to see if that will convince him to slurp up a good quantity of fluids. Greens like collard and mustard will really help with hydration as well.
Good luck and keep us posted on his progress.
The Zombie Mama is here!