Just because something is new to you, doesn't mean it is new, or revolutionary. Mark Berninghausen
The dried black larvae, if they are hard are stonebrood. It is fungal like chalkbrood. There is also EFB in there. The larvae that are twisting and turning yellow and brown. Sometimes the larvae start with what appears to be efb then chalkbrood or stonebrood finish them off. If the hive were mine I would feed Caspian solution. Short of that feed syrup, patties if you have them.
Sounds like the outside frame has not been built because lack of flow.