Working with ACES in After Effects is pretty tricky because AE’s color management is based on ICC color profiles, which isn’t how anyone else seems to do it. So at least as of early this year when I last did tests, the OCIO plugin for After Effects actually needs AE’s built-in color management to be turned completely off in order to work correctly, as OCIO becomes your entire color management system. You do still want 32-bit color depth in your project settings, otherwise AE will not work correctly with EXRs (which are 16-bit standard but a special “half-float” numbering system as I’m sure you’ve read. 32-bit EXRs are possible but generally unnecessary and not part of the ACES specification.)
Regarding the pre-ingestion transcoding, I believe that according to strict ACES spec your EXR files are always supposed to remain as ACES2065-1, and then each piece of software is tasked with converting to the other ACES formats for the current step of the process, but converting back to ACES2065-1 for export. So your first step would be transcoding your camera footage to ACES2065-1 EXR file sequences, then importing those to an After Effects project, where you would use OCIO to both convert to ACEScg and apply the ODT+RRT for your calibrated monitor. Then when you’re ready to export, you would need to use another OCIO instance in your composition to convert back to ACES2065-1. In your Output Module settings, I believe you have to specify 32-bit color depth, and you can embed an ACES2065-1 color profile but last I looked AE was not yet able to do that in a spec-compliant way (something about the color space metadata not being recorded correctly).