it will problably have time code burn in so syn in up and tell them to tell you what timecode is in . drop frame? film? pal (not likley)
you can have one main sesison to do everything or several depending on the size of it all.
one thing to think about is the metronome and the production track and or sequences made in the composers DAW.
cause u have to import the metronome midi into pro tools. maybe theyll be supplied as an audio file maybe midi.
maybe have separate cues or a fast way of soloing dialog, sampled music and or production track and or temp score.
the movie file has to be any format quicktime and less compressed the better, so try not to get a h264 or mp4 as those are usually for internet streaming and take a toll on PT processing.
as for export formats, it depends on the project and the mixer/composer as to how tight and organized the recording sync should be, thus if they import your recording via session data or audio file they know exactly where each cue is. it has to be stupid proof as u never know what others know.
i learnt the hard way cause a team working an a movie had this way of syncing stuff:
there is a time code and the audio starts 2 bars before the start of the audio file. so you synced 2 bars before the timecode.

which not only can get confusing but some cues had many time signature changes and some in the 1st 8 bars of a cue.
so get that part figured cause it can create chaos if u arent sure and the others are not sure. but it depends. some composers will know exactly where those strings goes others will struggle with sync.