You need to mix the elements together into a mono or stereo master track.
You need to know the file format the video editing system wants to see. Probably 24-bit, 48kHz wav files. After the audio is married to the video, it's up to the video to render the whole thing out. Not your problem.
Distribution will determine what formats you need. If you expect the project to be played on a TV, they need to consider PAL and NTSC. Not your problem. :)