timing would be tight. what matters is if you did the second b within the buffering window. if you were just mashing the second b...then it's probably gonna come out...unless it's a cancelable move, which i don't think it is.
that said...experiment with the buffer window. there is a point where you can delay the second b and get a straight b slash...provided again that it isn't a cancelable move, which i don't think it is...
the g in the middle probably isn't necessary, just better timing on the 6b~b
again this is all theory...i'm too far manhattaned beyond testing anything right now.
Ya there is no need for a G input (unless its helps your timing by occupying empty space), just stop a string half way through and start something else. Although some delayable strings may require a bit more practice like timing Yun's 6K into standing KKB, or WSA into standing KKB.
To be more specific, no hitting G doesn't lessen the recovery of the single 6b like it would in VF. You'd have to wait till that recovery window ended.