Renaming Fire as a Device, Alexa not listing active clients
I have two Fire TV units local to my house, all named properly by Amazon - meaning, if I go to Amazon, sign in, and go to Manage My Media and Devices, I see them named "Master Bedroom Fire" and "Living Room Fire" and if I look at the Fire menu under Settings, Device, it says the name of my device matches that which was set on the Amazon website (i.e. "Master Bedroom Fire").
If I go to my Plex server, however, they are listed as "Fire TV" and that's it. I can only differentiate them by the MAC address identifier next to their version number. I have tried unregistering them from the server, uninstalling and reinstalling/re-registering the device to my server, everything - nothing changes its name. There is also no ability to change the device's name in the Plex app on the Fire device, nor is there an option to name the device in the Plex server web GUI. I need this option to be able to differentiate between my two units, not only from the standpoint of managing them in the web GUI but also so that they can be controlled by name with Alexa.
While I don't want to present two problems in a single request, I have another issue as well - if I ask Alexa to change my default player, it says it can only find a single player connected, and sets it as default automatically - but it sets "Google Chrome," not "Fire TV." Which is odd because I'm literally looking at my master bedroom TV right now, looking at the open Plex app, which is actively playing music from my Plex server, and it's obviously not using Chrome as its player. The Alexa app is registered properly to both my account and the Plex Media Server per the setup guidelines.
I just updated both the Plex app and the Media Server, which are running 220.127.116.11 and 18.104.22.16885, respectively. Everything is hard-wired on gigabit ethernet. I can watch content from Amazon and through Plex, even full-bitrate Blu-Rays, with ease, so it's not a connectivity or setup issue, just a manageability and Alexa integration one.
Any clue? Without the ability to rename the Fire TV in Plex, I can't tell them apart. I also can't possibly tell Alexa which device to play things on if I can't rename them, and even if I can I can't seem to list them with Alexa.