This app was mentioned in 3 comments, with an average of 1.33 upvotes
This app seems to work okay, and I think that Plex has airplay support as well...
Have you tried using Airserver connect?
this works for airplay receivers (and is free at the moment, instead of the usual $5)
https://play.google.com/store/apps/details?id=com.appdynamic.airserverconnect
I'm using it on my Windows computer (AirServer software; not free), with my Android phone right now.
If you could carry any kind of airplay receiver and solve the wifi issue...
EDIT: another option - mhl to hdmi! https://www.amazon.com/Samsung-MHL-HDMI-Adapter-Packaging/dp/B005LGUDKK?ie=UTF8&*Version*=1&*entries*=0