The ANG units were the only units that got the E-Model, they were not re-engined they were traded out for R models, hand me downs from the active duty. I believe they had to retire the E's because Boeing wouldn't continue to sign off wing boxes. But I'm not 100% sure. The E sure was a nice plane to fly, but it definitely couldn't perform in the desert like the R's can.
Oh and I am pretty sure that at my last electrical sim, the system would still work on on generator. Put a high load on that gen, but things still worked. At least for a little bit, till that damn sim instructor decided to make my sim more "fun"