Great stuff. Couldn't you just have stacked the 3 shots in PS? It worked out well. These are such neat subjects.
I used LR to open all the Files as layers in PS and then in PC, Edit - Align then Edit - Blend but there was a lot of ghosting where PS was "fooled" into overlaying some the OOF anatomy over the in-focus bits.
So, I undid the Edit-Blend and then manually blended the (already Aligned) sharp bits via Layer Masks. This way, PS did the heavy lifting and all I had to do was touch up the result.