You'll need to keep up some of the basic therapy.
You'll need to do direct work for your abs, obliques, obliques and lower back.
You'll need a way to work your legs, a bunch, without adding to the workload on your lower back.
You also need the big moves, because in the world, your body moves together. And they are the best for strength. Because you're weak now, the loads should be based on your current strength.
Off the top of my head, it sounds like Westside.
-Daily rehab stuff for your weakest muscles.
-Reverse Hypers and all kinds of abs.
-Box Squats to overload the hips and underload the back.
-Sled dragging for legs and conditioning.
-Controlled volume on the main lifts.
-Lots of work on single joint exercises to build up lagging stuff.