Maybe it could be setup in the Echo account and act as a "Playlist" of sorts... only a "Playlist" of commands....
What I did was to find a way to have Alexa send commands to a Mac on my LAN. Using an app called HAM Bridge, those commands execute scripts on the Mac to tell a variety of apps and devices what to do. These scripts can accomplish quite a number of things, including sending TTS back to the Echo via Bluetooth.
Unfortunately, Alexa can not talk directly to devices on your LAN; everything that Alexa responds to originates in the cloud. My workaround for this was to create a skill that directs requests to SmartThings, and a Smartapp that pass them on to the Mac (as well as other SmartApp handlers), which then issues responses back to Alexa.
It all works quite well, and I am thankful for Amazon providing free hosting for my skills function, but it would be much nicer for the do it yourself'r to be able to directly pass Alexa's output to a local device.