Yes – the license is platform-agnostic. However, you must download the correct installer for each OS.
You're allowed to move your license to new hardware: emedia cs2 license key
If you own an older eMedia version (eMedia CS1 or original CD-ROMs), eMedia offers discounted upgrades to CS2. Contact their support with proof of purchase. Yes – the license is platform-agnostic
eMedia CS2 was released circa 2010-2015. Older keys may still work, but: Contact their support with proof of purchase
No – CS2 requires Windows or macOS. Chromebook users can try the Android version of eMedia Piano (sold separately) or use remote desktop to a PC/Mac.
No – after online activation once, the software works offline indefinitely.
Officially, CS2 is legacy software. eMedia provides minimal support but still sells it on some platforms. Their current flagship is "eMedia v3" (version 3.x). You can often upgrade for $20-40.