Best way to get notifications from HA? (iPhone/watch/whole house audio)

Configuration
1

I’m just getting started with my configuration and am pondering notifications. “The washer is done!”

At first I was thinking whole house audio (I’ve got Airport expresses everywhere hooked to speakers) but if someone is napping that might be annoying. Still would be nice to setup.
Can HA broadcast to AirPlay devices? (I also picked up an Audiocast M5 to play with)

I’m thinking the better solution would be to notify on my phone/watch.
What’s the best link for this? I’ve used pushover in the past for other projects.
Is there an app that might allow acknowledgement of an alert? (back to HA, so it can act one way or another)

Can HA do SMS? Can it manipulate a voip system? (I have 3CX for the home phone system)

2

not sure about airplay, I personally use a combination of chromecasts and iOS notifications.
I prefer iOS notifications over pushover as it give me the ability to send actions/commands back to HA straight from the phone/watch without having to open the app (I use it for Alerts a lot)