hi,
first of all, you´ve allways have the possibility to transcode your video to an eding-codec like uncompressed, pro res or foto-jpeg.
a tool in every editors toolcase would be MPEG Streamclip, the swiss knife for free – PC and mac.
now to your questions:
1. in case your clips are 25/50 fps you should go PAL, all others should go NTSC.
2. even 24fps will we encoded as 29.98fps NDF with 3:2-pulldown, so I wont see a reason why progressive should be a problem.
note: if you need to create a DVD for int. market you should go NTSC as well, because DVD-player in US wont play PAL-framerates, but PAL-players will play NTSC-DVDs.
cheers
danny