I would edit at 1280x720p 23.976fps…
The 1920×1080 can be scaled down.
I would take the 25 fps material and use ‘interpret footage’ to get it to play at 24 fps. The audio will pitch down by 4%…but depending on the material, it may not be a problem if there is no footage of the same people talking, etc on another clip that isn’t speed-converted.
The 29.97 material will run reasonably well on a 23.976 timeline with no adjustment…but check ‘frame blend’ by right-clicking the clip on the timeline to reduce the ‘gallop’ effect in the frame cadence if the action is causing to many motion artifacts.
While converting everything to a mezzanine format (like ProRes) seems like a good idea…and make no mistake, it would probably run easier that H264 material…it makes gargantuan files and if you aren’t using that step to do some kind of conversion beyond just creating massive files, you won’t gain much beyond a lot of data footprint on your drives.
PPro is designed to deal with mixed format material…you might as well use it if your machine has the power to handle the processing…
TimK,
Director, Consultant
Video Producer at I-CAR