The session, regardless of what software you are using, must have a sample rate of 48 kHz at 24 bits: this is standard. Next, make sure that your session’s frame rate matches that of the video: this is very important, and will help you avoid sync problems down the line.
When recording you will not have time to create the proper perspective splits for each character. This will be done during the editing process later on. Speed is of the essence, so tracks are assigned in rough groups (unless otherwise specified by the requirements of the project):
1 - 4
5 - 8
FX (optional)
Principal characters, or a conversation between a principle and a secondary character
Secondary characters, group specifics, walla (stereo)
FX track for phone conversations, PA announcements, radio / TV / walkie-talkie, etc.
Alternatively, for certain types of projects - particularly animation - each character is recorded on a separate track.
When editing, tracks are assigned according to guidelines set forth by the production company so that when a session is delivered, the mixer will know where to find each element. The track layout may resemble something like this: