I am editing in Premiere Pro. The native is .h264. Should I render edits and to continue AE and VFX in MOV, AVI , MP4 or other? Final result will be for theatrical release which has then be converted to ProRes file.
From what I understand, once you drop the clip into a sequence, it will ask you if you want to match the sequence settings to the footage, click yes. You can edit h.264 natviely, and output to proress with any issues. Just ensure frame-rate is the same, and check the color on your final output at the end of the edit, when you export. Sometimes, exporting to prores, I've had some color look slightly different, but not that big of a deal. There are a ton of videos on YouTube as far as best ways to export to ProRes, but for me, best quality and frame-rate is the most important for me for exporting. Theatrical release and acquisitions people may want to a different format or flavor of ProRes, so I'd check that as well. Future congrats on your theatrical release !
H.264 has the following disadvantages when using as an editing format:
1. H.264 is mathematically intense. It takes some serious computer horsepower to decode its compression.
2. Because it is so mathematically challenging, it takes longer to render H.264 files than other formats.
3. As H.264 is an 8-bit format shot by HDSLR, which means you are potentially compromising your effects and especially color correction and composing gradients.
4. H.264 does not integrate easily with other video formats.
Therefore, it would be ideal for you to choose Premiere Pro natively optimized MPEG-2 file format.