Thank you all, and specifically sitzmark for the detailed email and suggestions.
Kevan - thanks for that suggestion. I read up on that a bit and it appears like a great piece of equipment, but I think a bit above where I'm at right now...and I worry would be a gateway into a very expensive hobby!
I'm now thinking something like this to control some hard wired outdoor speakers:
https://www.amazon.com/Pyle-Bluetoot.../dp/B010U5EGKE
And maybe a Sonos unit or two to improve on the echo units we have in a few rooms in the house. I think I could connect that Pyle thing and the Sonos to the Alexa and then have my "play music by the pool" type command options...