Jay,
Once in RB you can generate new tracks there also.
Right click a new blank track and choose 'Select and generate Realtrack' (or Realdrums).
May save you some steps. That way it just generates onto its own track for you right away.

If it was me I would first open the BiaB song in RB, then start bringing the individual wave tracks you created into the new RB project (so you have the tempo/chords and A/B parts from BiaB to use for generating in RB).
Then try generating new tracks (and recording your own) inside RB.

Experiment with different style combinations; it's fun!
Take advantage of the Multiriff function that generates the track you choose but gives you multiple variations to choose from.

Find the point where you feel comfortable moving to RB, instead of going back and forth. It may save you some time, and 'creative juice' time at that.

I do not work here, but the benefits are still awesome
Make your sound your own!