It is feasible to use Reaper for FOA multitrack editing/mixing after using Adobe Audition to clean, balance, and fix FOA clips. As Audition only supports up to 5.1 channels and is not specifically made for ambisonic multitrack, some workarounds are necessary.
Even if the other tracks in the project contain non-FOA clips, like stereo clips, they must all be set up in 5.1 in order for it to work for FOA sessions. To achieve the greatest outcomes, you must only utilize plugins created particularly for multichannel/ambisonic, such as the IEM Suite by Felix Holzmüller.
You can briefly add the Rode Soundfield plugin to the Master track to listen to the outcome through your audio system, and you can temporarily add the IEM BinauralDecoder plugin to the Master track to listen to the result on headphones. It is vital to make sure that Audition does not apply any bandpass or other filters to the tracks, or any metadata, and that it remains neutral with regard to all the track/clip channels, particularly the 4th channel (LFE).
In conclusion, it is possible to use Reaper for FOA multitrack editing/mixing after using Audition to clean, balance, and fix FOA clips. To get the greatest results, however, some workarounds are required, and it’s vital to make sure that Audition remains impartial regarding all the track/clip channels and that you use plugins created for multichannel/ambisonic audio.