S2 compatibility with play5, and connect amp

You haven’t provided enough information to know. It depends on which PLAY:5 you have, and which CONNECT:AMP. It’s entirely possible that you can run them all on S2. I’d recommend reading the announcements thread:

My Sonos system screen says for:

connect amp: Sonos OS; S1

play5: Sonos OS; S1

Frankly, I’m absolutely BS that Sonos would even consider developing a subsequent OS that

doesn’t support their own legacy hardware….if they don’t offer me a replacement for my amp and play5, I’m seriously considering BOSE.

When issuing off-the-cuff threats, one should do their research.  Bose recently abandoned an entire lineup of smart speakers that were being sold right up to the day they replaced them with a new line of smart speakers that were 100% incompatible with the old.  On the other hand, Sonos split with units that were designed well over a decade ago and haven’t been sold in 6 years.  

I am sure that you and Bose are made for each other.  Good luck.

You maybe right, but I’m still pissed!

https://community.bose.com/t5/SoundTouch-Speakers/SoundTouch-Officially-discontinued/td-p/561258

Boom!  Discontinued and replaced by a whole new lineup incompatible with a speaker you could buy the right up to that day.  If you dislike Sonos, you are REALLY going to dislike Bose.  

Yayayaya—I get it, I’ve got to suck it up. I don’t have to be happy about it though...

You can use third-party apps that can control both S1 and S2 systems from a single app.

Ok, what is the name of that app?