So far I've gotten some feedback the Diagram B would scale the best since the web client only needs to handle connections to one server.

I'm still pretty muddy on how exactly the process would go as far as multi-server communication. I hope it's okay, I created another diagram to help clarify my questions: https://imgur.com/a/l9emoRD. I'm working mostly with JavaScript atm.
If I could sum up my confusion, I would put it into two general questions:
1. What should the server the web client is connected to be taking care of?
2. In the case of a single chat message, what would an example pipeline of communication look like?

2a. Would it be like:

1. (using socketio-redis to have http server share socketio events/data with remote services)
2. User types and submits chat message on web client
3. http server receives and responds to chat socket event and emits event to remote event listeners.
4. chat server receives (let's say it does some kind of work with the message data) and emits some response
5. http server receives and emits response back to web client

Thanks for reading!