Scott — Your image 5 is interesting with the set of “staggered” transformers. As an example of how ingrained 240/120V delta and open-delta service can be, here are some [MSWord] pages from {El Paso Electric} utility’s distribution standards. There are some charts for determining acceptable “combination” 1ø and 3ø loads for various-sized sets of transformers. See
Delta Loading [Small aside — I’d hate to have to pull the fuses on the righthand set of cutouts. I guess you are supposed to stand on the platform to do it.]
