So I got my new Square EMV reader. The messages in the app has been updated to mirror that of a large store.
It flashes "Processing Do Not Remove Card" just like a big retailer. And when approved you'll see the AID name ("Visa" "MasterCard" etc) of the card flash really quick before saying "Approved Remove Card" then signature screen comes up.
Reader Ready stays black up on the status bar of the iPhone.