Yes that’s why there is AfterCodecs ! It doesn’t need Quicktime (and never will) to run so you should be safe now ;)
Please open a new ticket about AfterCodecs, don’t forget to send the .log file generated by AfterCodecs and information about your setup !
Please follow the manual instruction in the .pdf given with the AfterCodecs downloaded archive
Be sure to be using x264 (and not x264 RGB or x265), with the quality slider <= 98. If it still doesn’t work, choose the H264 Main Profile
Not yet, sorry. If you want to discuss this feature and what you need, please open a new ticket :)
Not yet but this a planned feature don’t worry
H264 is the norm and x264 a software encoder that implements H264, faster and of better quality than encoders from Adobe or Quicktime
Be sure to set your AE project in 16 bpc, it will export to AfterCodecs in 16 bpc (even if you select “Millions of Colors” instead of “Trillions of Colors”)
Select “[A] Hap” and export in RGB in the AE settings. Exporting in RGB+Alpha will automatically switch the codec to Hap Alpha.