working cross platform in HD, LE, and Free?

[Archmart]

Hey Hey!

I'm working primarily in an HD studio (Mac).
Two of the band members are working at home on (Mac) LE systems to do basic editing.

So far this has worked well. We spend a day tracking in HD, take the files home on Firewire drives, and then edit the various takes in LE. When we come back to HD, everything is fine.
(of course we have to switch playback engines and some sends are unavailable in LE, etc.)

Now, a third band member also would like to edit his guitar tracks at home, but he's using PT Free on a windows machine. The goal would be simply to listen to takes, remove some takes from the session (noting for the rest of us which he'd removed so we could also), create new tracks for primary parts; secondary parts; etc., and to create playlists within the tracks for the different takes. (I would give him session files with a stereo mix of drums, bass, etc. so he could still have 6 tracks to work with. He would then send me his session files, and I would "Import Session Data" into our main (HD or LE) sessions from his Free session.)

So can anyone tell me if...

1) Is this just plain impossible for him to open a Mac LE session on his PC with Free?
2) Is it going to be impossible for me to "import session data" from his Free session?
3) We've been working 24 bit/ 44.1k, is this a problem for Free?
4) Are there any other considerations I'm not thinking of?

Thanks so much.

Archmart