@VRC Regarding disabling the invisible walls function, currently cannot be enabled/disabled in ap manifest as pairing UI does as you stated before.
We had our internal discussion for other approach to help you disable the virtual wall settings for these 100 HMDs, but the viable way would required function verification/building service apps/testing and can not fulfill your schedule requirement.
On the other hand, this settings can be configured via Settings >> More Settings >> Headset & Space >> Safety virtual wall.
Therefore, as the timely fix to your requirement, we would suggest to manually modify this setting when you waer the HMD to check in COTA config is correct in your workflow:
1. Use kiosk COTA to configure the device
2. Check if the HMD Kiosk COTA is configured correctly
--> When do the configuration checking on HMD, manual disable the virtual wall via Settings >> More Settings >> Headset & Space >> Safety virtual wall.
We sorry for your inconvenience for the manually config before next SU release, and please let me know if you have any further question or any thing we can help here, thank you!