Thanks for your response.
There are two options to config per-program sandbox policies.
SBPL (Sandbox Profile Language), a low-level configuration language.
Entitlements
As you mentioned
The only tricky thing is that the child’s executable must be signed with the com.apple.security.app-sandbox and com.apple.security.inherit entitlements
If the child executable is not signed with entitlements(app-sandbox), but using sandbox_init with SBPL policy after child process is launched to enable its sandbox capacity. Can it pass Mac App Store rule? Child process is also sandboxed.
I saw some developers experience about the sandbox entitlements Cannot submit mac app because com.apple.security.app-sandbox is removed from entitlements
What's more, adding one prerequisite to my question before,
Do you have any suggestions for my application scenario, sandboxed child processes having its own privilege not inheriting from sandboxed parent process? This application plans to deliver to MAS.