Can fluency sound natural with fluency shaping tools?

Sure, but maybe not at first and depending upon the severity of your stuttering. It is best to practice slow, exaggerated speech to FEEL the vibrations in your throat. I can't empahsize FEEL enough. "Turning on" a contrived way of speaking will not work, but feeling the whole system together will. I love that feeling of vibration in my throat and it keeps me fluent. It takes hours and hours of practice, but it works for me and many clients I treat.