You can try different stuff on knockdown against Noel but, as mentioned earlier, the only truly safe option relative to Rachel's other choices is non-summon meaty 5B.
I highly recommend trying it out in training mode to see for yourself (I did this once Polka stated that meaty 5B was the only answer so I had to see it to believe it). Make Rachel your dummy opponent with Noel as the character you control and record 3C > summon > 5B. Have Noel try stuff on her wake-up. Run through the list of Noel's moves. Then later try meaty 5B and run through the list again. Try Rachel's 6CD, dash-in 2A, whatever else. Eventually you will see the horrible truth
From all that you will learn why meaty 5B is the only way to go.