Q: "I want to know if non DCC engines will run on E-Z command"
A:Yes. But be carefull, DCC uses a higher voltage and it is possible to burn out
the non-DCC motor
Q:"I want to know if I can change my command controller after a while too."
A: Yes, you can use any DCC controller you want. The EZ is just a simple and
very basic introductory model.
Q:"What engines types run and do not run on E-Z Command?"
A: Just about any DCC equiped loco should work.
IF you you have Cable or DSL, here are some videos made by Bachmann about
EZ command to get you started.
Just remember that Rome was not built in a day.