Yes, you are correct in that you can use DCC and Railpro on the same layout. Railpro doesn't care where the power comes from, as long as it's there. If you want to run DCC locomotives I recommend using DCC power supplies so that DCC locomotives can be controlled, and Railpro will just use the power from it.
I've run Railpro on DCC layouts almost exclusively and there has never been an issue, even while DCC trains are running.
-Kevin