It is not difficult to understand.
“Apps are NO LONGER ALLOWED TO USE APPLE EMOJI in non-keyboard based situations. Means if your app displays apple emoji anywhere without a user having it typed in, it’s illegal.”
So .. basically it is not illegal when they are published by users in posts (whether they are topics, replies/comments or personal messages) or even in the chat. The problem could be in reactions. Since the keyboard is not used to enter them, only selected. I don’t remember, though, if apple emojis are used with reactions.
EDIT:
Anyway i’m using the iphone and when i put the “smiley” emoji, with the composer … it’s not the apple emoji. The Apple emoji is the one I publish with the Apple keyboard. So what’s the problem here? We just have to see if reactions plugin use the Apple emoji but i really think is the same of the composer, so i don’t think why should be a problem.