I can in fact confirm that you can mirror the note 5 WITHOUT WiFi, with the Amazon Fire Stick. I first tried the chromecast today but that does require wifi even though google had earlier said they were gonna update it.
The initial set up of the fire stick DOES require WiFi. But that is a one time setup, to register the device and get updates. After that its simple
1. Turn the TV on with the firestick plugged into HDMI.
2. Goto settings, then display, then enable Mirroring
3. On the Note 5, enable mirroring and select your firestick. (After the first time it should automatically connect.)
4. Wahlah! Yer mirroring. This is great. Now I can stream netflix, or amazon prime, (or anything i want) from my phone. Wooohooo!
Sent from my:
Beautiful Note V
64 GB
Black Sapphire
Paired with Samsung Gear 2 Neo
Sprint PCS