Will it also be available for a group chat?
I don't think so. So far, I've only seen 1:1 chats. Even when you add a contact, you can only scan 1 contact address.
As for the rest of your concerns, I'd let the team answer that.

~snip~
Current security features are biometrics and a Pincode. You can back up your wallet's Mnemonic code too if you wanted.
I wanted to try myself, but maybe you can help so I don't have to... install them on my phone to try myself, hahaha (sorry, old phone, it always runs out of memory to install new apps). Does the confirm button works like you guessed (to confirm a transaction)? Or do it trigger another thing?