I'm late to the replies about video editors... but I use HitFilm. It has a free version which is VERY powerful.
It can also be used to export the audio separately for editing, then you can import it again after doctoring.

Unlike most free video editors (which typically let you combine images or video clips sequentially and blend them together in a variety of ways) Hit Film also lets you create composite scenes (in which many elements are layered together to create a totally new scene fabricated from pieces... like the CGI scenes in movies)

For example, Adobe Premiere is basically a video editing product, but its companion is Adobe After Effects, which is a compositor. Hit Film is like getting both Premiere and After Effects for free in one package.