FMP-My Individual practice for the Gig

I have just been recapping my chords and singing style of the Songs Castle of glass by Linkin Park,Wavin Flag by K'naan and practicing the chords for American Boy by Estelle because Alyx is Singing it. for performing for the Gig,My band members are still rehearsing with other people and they are very busy,I had also been practicing,What I had been learning in my Instrumentation technique lesson and other type of rehearsals like making my own music while playing piano.But my actual focus is rehearsing and performing the songs for the Gig. If Reece,who plays the Guitar,want me to play bass,I practiced by playing the songs with right hand to play the chords and using the left hand an octave lower to play the roots of the chord which match the chords I am playing.