Grouping Airplay-2 with Chromecast speakers

I’m still looking for a way to bring my beloved beolit 12 into an airplay-2 network together with an A9, BS1 and a few ATVs.

I know that one way is to buy another ATV (with hdmi splitter) or an airport express with the new few update. however, ATV/splitter makes no sense. and the AE does not have AC wifi, so i doubt will be stable.

I’ve been thinking whether it would be possible to stream via airplay-2 to the A9 and then have the beolit join as chromecast group (by connecting a CCA to the line-in).

Would this work or any other ideas?

AE will work. It's stable. As long as the AE has a decent connection to you main router. 

I'd prefer an AE in my set-up over a chromecast - airplay 2 combination any day.