Reply to "Beginner question: Can one transformer do it all or do I need different brands?"

I, too, would recommend an MTH Z4000 or a Lionel ZW-L. Both are excellent power sources (I use the Z4000) for any AC locomotives. I would forget the CW80 altogether, just based on my own past experience with that transformer. You already have a good number of powered units, so save up a bit more $ and get yourself a transformer that will handle your needs as your roster continues to grow.