They are looking for a guitar who owns a bass, so in fact the guitar will play the bass on the tracks that need keyboards. The bass needs to be near the kick drum, so that means the guitar which is playing the bass will be on the floor. Now they had a drummer and singer with an on-board keyboard which also played bass, but with the guitar playing bass, then the keyboard will have to sing, but only on the songs that need trumpet, which will be covered by the guitar or bass or drums. Anyway - it won't work. I'm out.