Mac software to edit audio track for a video file?

A couple of times now, I've 'cuffed' a movie to make it family friendly, by reversing any bits of swearing - "We want ze neekuff money, Lebowski" etc. (the latest was Beetlejuice which has a single f-bomb in the middle). It's a bit of an involved process, involving extracting the audio stream with ffmpeg, editing it in audacity, then recombining it back with the video stream with ffmpeg again. Is there any free Mac software that would let me do this in one hit? Ie, be able to directly edit the audio stream (ideally with a reverse function), and save it straight out into a new video, without mucking about with reencoding and ffmpeg?