Hello,
I absolutely feel, I am the perfect fit for this project. The reason, we have create two apps, 1 for messaging with classifieds and other exact WhatsApp clone with WebRTC as calling engine.
I do feel for you because I know how difficult it gets to make it reliable when there are so many scenarios like app in background, constant online/offline status and many things related to that. I can give you detailed consultancy on this, and if needed, my team can help with development too(Backend, iOS , Android , any). My two cents on your problem.
1. You will have this unless you do not implement an IM protocol as offline/ online should be done real time. Regarding network switching, I can guide you what to do.
2. This is most probably due to signaling module not communicating properly, believe me!
3. Video profile, I really need to know more about it. Latency, we can chat about it later.
4. Need more details.
5. What singling server is in place right now? I do have couple of recommendations though if you do not have any!
6. No issues, its a standard web programming.
Looking forward!
Thank you,
Zeeshan Arif,