Is there a way to add "real" stickers that behave like Sticker App stickers to your custom iMessage app extension? The only examples I've been able to find use use MSMessageTemplateLayout, which as far as I can tell always shows the app icon and doesn't let you peel the stickers and stick them onto other messages.
"Pealing" is a feature of MSStickerView. In other words, all MSStickerViews can be pealed.
A nice walk-through iMessage Extensions is this Apple Sample code - IceCreamBuilder