I found the problem why it didn't work with quick edit or quick reply and I fixed it. The problem was that vBulletin's javascript function that was supposed to encode it doesn't work. I replaced it with
encodeURIComponent(), a function that's been built into JavaScript since like 2003. The reason it only worked in the advanced editor was because it didn't use javascript.
But that's fixed so you can use emojis in your posts and PMs now.
🙏🙏🙏