I can probably do what you're asking for at a decent lower price point, just need to talk over some more details concerning exactly what you're trying to accomplish. You're going to record video from a webcam or attached camera or some source. Then you're going to have 3 different recordings, from concurrently attached microphones, or the same microphone just during 3 different times, and you want to replace the audio in the recorded video with the mic audio? If my interpretation isn't correct, we can always discuss some details, but the project itself should be fairly straightforward to implement, to just create a program that does audio dubbing essentially.