Just confirmed, you do not need to be on a Wi-Fi network to connect using Miracast. All you need is the Wi-Fi turned on the phone and the Miracast adapter connected to a projection device
Well, Miracast is Wi-Fi Direct, it doesn't use your local network, the stuff connects directly. You don't even need a router.
I'm unsure of how the Microsoft solutions work but I just ordered the Actiontec Screenbeam Mini2 off of Amazon for $39.99. It has all the Miracast and Wi-Di needed for this stuff. I'll be streaming wirelessly for my Flex 10 Win8.1 setup, my Lumia 630 and from this Android tab I ordered too.
The Microsoft Display Adapter goes for $69.99 on Amazon, I saved enough on the difference for me to snag some sweet looking Bluedio H+ Bluetooth headphones. I should have my package Tuesday. I will let you know how well it works.