You can drag the 1602 piano track to DROP MID, drag MID to the the song folder, in BB > File > Import > import that midi,
you can now edit the notes in the piano roll.
The RealCharts are recorded on the same Yamaha acoustic/midi piano, so they should be identical.
You can set the midi track to Sforzando > Piano, it should be the same piano as the RealTrack.
With RealBand, yes you can import the track back to BB as Audio or as the midi RealChart from RealBand (just enable RealCharts first in the Generate menu).