on larger productions the sound and color and vfx are normally done at the same time after the movie has picture lock.
one exports the audio for sound work from edit program, normally in OMF, and a reference picture for sound editor in mid quality format (ideally intra codec one like proresLT fullhd or similar).
Then exporting a playout for online editing reference and exporting the image to XML for transferring it to online and grade. This may vary a bit from production to production but generally this way.
Online editing, linking to the camera originals. then transferring the image to color grading and the select vfx shots to VFX work (ungraded vfx shots in fullrez 16bit TIFF or dpx for example)
Grading the image.
GRADE VERSION PLAYOUTS AND AUDIO MIX PREVIEWS ARE TRANSFERRED BETWEEN AUDIO DEPT AND PICTURE POST AND UPDATED TO THE AUDIO AND GRADE PROJECTS WHEN NEW VERSIONS ARE READY
Finishing the grading, vfx, titles etc. and exporting the image out with reference audio or without audio in the required formats and resolutions (jpeg2000, TIFF, proreshq, prores444, etc. in fullhd, DCI 2k scope, DCI2k flat, 4k, etc. ) frames 1:1
Finishing the sound mix and exporting the different audio masters (R128 tv mix in 5.1 and stereo, M&E mixes, different stems, Theater mix in 5.1, ATMOS, etc.) and sending the files to picture post in wav files . In some PAL countries like Finland it is normal to do 24fps theater versions and conformed (sped up) 25fps tv sound mixes on both the final mixes and stems
Mastering to DCP, prores, etc by combining the audio and picture. PICTURE FRAMERATE CAN BE CHANGED AT THIS POINT WITHOUT QUALITY LOSS by conforming 24 <---> 25 and adding the corresponding audio tracks
Different customers need different files, framerates, audio channel order, etc.
Subtitling files can be done by:
1. sending the final dialogue lists for translations
2. sending the picture locked timecoded edit playout for timing
3. sending a timecoded preview of the final movie for timing check. separate preview files for 24fps and 25fps timing are needed
---->subtitles delivered to picture post and customers in .890, srt, etc. formats for dcp, tv use, bluray/dvd use, web screeners, etc. and combined to the masters if needed or delivered separately per customer orders
Audio, vfx, grading, online is not practical to do if the edit is not locked, one needs to do the changes partially manually which wastes lots of time and resources. so do the picture lock first and then the post, you will make your post crew happy by not ordering constant changes on the fly