I'm not sure about the battery management boards yet. I am hopeful that I will be able to salvage the packs. It hadn't occurred to me that the tabs were welded to the bussbar the full width of the tab because of the bussbar not being welded across the full width of the bussbar. It makes sense now that I think about it. (Edit-I correct my correction. The tabs are wider than the weld. There may yet be a salvageable bussbar after dremeling the weld)
If you look at the following pic you can see where the bussbars for adjoining groups of 3 cells are spot-welded together. It is at that junction that I think I might be able to cut out and spot-weld in a new 3p group.