===NO SELF PRAISES===
Hello Sir,
I am available to start your described project immediately as per following flow you mentioned.
1. Add fb ads to your webview app.
2. Control admob or fb ads shown in app through json server.
3. Control web address from json server.
I am confident enough to complete this task within 3 days. I will be honoured, if you tell me some more details, please.
Regards,
Muhammad Nouman Ali