Multiple named Instances and Availability Groups
Your proposed setup looks okay to me; as long as both nodes are in the same domain, that should work fine.

What you need to resolve is the ability for each server to get to the other on the configured ports. It sounds like 5023 is being blocked by a firewall rule of some kind, or that you haven't used the same port consistently throughout the configuration of an availability group. 

I've come across the error you're showing and in my case it was actually an encryption issue. Please check out the following posts in detail:

http://sqlperformance.com/2013/04/system-configuration/troubleshooting-alwayson

http://sqlperformance.com/2012/10/system-configuration/dedicated-network-availability-group