Yes I am able to see the ATV for AirPlay from all iOS devices. Yes I can control the ATV with the OLD Remote app.
My routing is handled by a Verizon FiOS Actiontec MI424WR Gen 3i at IP address 192.168.1.1. Sixteen (16) static IP addresses are manually configured in the range 192.168.1.2 to 192.168.1.99, and DHCP addresses as needed are assigned automatically in the range 192.168.1.151 to 192.168.1.254.
IP addresses 192.168.1.100 to 192.168.1.150 are reserved for Verizon FiOS devices that are connected to the Actiontec router via a COAX connection (e.g., Arris set top boxes).
My WIRELESS network is handled by two current-generation Apple Airport Extremes connected to the wired network, with static IP addresses 192.168.1.2 and 192.168.1.3 as reserved by the Actiontec router. They both operate with routing off in bridge mode. Both these Airport Extremes create a wireless net of the same name in different physical locations. On wireless devices that can support it I regularly seen data rates north of 700 Mb/s.
Depending where a wireless device physically is in my location, it connects to whichever Airport Extreme that provides the best quality signal, and an IP address as assigned by the Actiontec router in the DHCP range.
The ATV is connected to the wired network at 192.168.1.4.
It is beyond my competence to say if "multicast packets between wired and wireless subnets" are being properly routed in the architecture described above.
I experienced no problems setting up the OLD Remote app in this architecture. It in fact still works.
What do I need to do to set up the new Apple TV Remote app?