So, clearly, the attributes 0x8000000000000001 and 0x4000000000000000 don't seem to help. Although 0x4000000000000000 hides the drives from being enumerated, it causes issues with WinRE.
Your only option is to extract the WinRE.wim (~600 MB) file from Windows ISO and replace the existing WinRE.wim with the Windows-default WIM. However, if the WIM you're using has been injected with custom drivers and tools, you'll miss them. Backup c:\windows\system32\recovery\winre.wim to a safe location.
Extract winre.wim from ISO (using 7-Zip) and place it there.
Then reduce the size of WinRE partition to 900 MB.
Set the WinRE path again using ReAgentC and enable WinRE.
Boot into WinRE to test if everything is working well.