If you are an ios based family (may even just work if you want to control it from a single tablet like an ipad) I built mine around airplay 2. If you are android (or something else) this is probably not worth it then.
I went the whole airplay 2 route using a few sonos speakers (sonos one and a couple of the ikea speakers). I also have a few apple airport express 2nd gen's that also support airplay 2.
It works pretty easy. Whatever I'm listening to on my phone, I just airplay it to all the rooms I want it to play in. If my girlfriend wants to listen to something in the bedroom while I'm listening to something outside we can do that too easily.
It works fairly well.
The only issue I have with it is audio sync. If I play on all the sonos devices they are great at keeping all in sync and it sounds nice through the house. If I mix them with sonos and airport expresses it eventually gets out of sync. But I don't really mix them often.
In terms of cost (all in CAD), I got the airports for $30 each used off of kijiji. The ikea's I got for $125 each when they were on sale, and the sonos one I got from Amazon at $120 on some crazy deal.
If you want to centrally control it, you can get an ipad and set it up with your services and control it all from there. But we just find it easy to use our phone as we listen to a lot of podcasts and its nice to continue where you left off in the car etc.
My integration with HE is very basic. I don't see a need to really do much with them. All I do is have an automation that resets the volumes on them after we are done playing. That way it never starts off too loud when we start playing something.