I found some time to test with the two devices I have at home
- Samsung BluRay Player BD J5900
- Microsoft Display Adapter V2 (link to German MS page, can’t find the device on their US pages)
Both work and I can mirror my phone screen on the TV.
The MS page says, the adapter supports “Wi-Fi CERTIFIED™ Miracast®” so that obviously works with the FP3 
The Samsung manual speaks of “DLNA Cast” which has to be enabled on the device (i.e. the phone). I honestly have no idea if that’s the same thing or not 
P.S.: I remember that in the Ubuntu Touch groups a lot of people said that screen mirroring didn’t work well except for the MS adapter and that was true for my FP2: with Android I could connect to both the BluRay player and the Display adapter, but with Ubuntu Touch the connection to the BluRay player froze after roughly 10sec. So it does seem to matter what other device you want to connect to, even if they in general are supposed to support the same technology.
P.P.S.: I think I had to install a firmware update for the MS Display Adapter first and that was only possible from a Windows machine