Same-day, or even real-time editing is relatively easy–but you need a crew. An operator for each camera, a sound person to work the audio mixer, a CG person for overlays and titles, a recordist to make sure everything gets recorded properly, a technical director to work the video board, and a director. An AD would be good to have, as well. And if your mics aren't fixed, you may need an audio crew for those. It's basically a live-to-tape shoot.As others have noted, anybody who tries to do it as a lone shooter is most certainly asking for trouble.
