You're right, I suppose it might be possible via NFOs, if the third party media manager is essentially managing the content of the single/shared actors folder, but it's not the "normal" way of working for Kodi.
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.