Any factory O-scale stuff you buy from Lionel will not be DCC compatible, that's something to consider. I think you'll come to grief if you try to run DCC and either DCS or TMCC/Legacy at the same time on the same track, they will fight and lose.
I don't do DCC, so it made my life easy. I can run DCS, TMCC/Legacy, and any of the LionChief flavors at the same time on the same tracks.