So from what I understand Emojis just have to do with the font.
Is there a text message app that either loads the font from a remote server or updates more frequently then the Android OS?
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Textra SMS might be a good one. It lets you choose the emoji style and source, so if the source you choose is more up to date you can see them. Here is from the app description:
Get all the latest (Unicode 9) 2000+ Android, Twitter, Emoji One & iOS style emojis including diversity (skin tone). Just pick your preferred emoji style and express yourself!
You can download it free from the Play Store: https://play.google.com/store/apps/details?id=com.textra&hl=en
Similar to it is chomp SMS, which also lets you choose the style and they claim:
Provides all the (Unicode 8) latest 1600+ emojis including diversity (skin tone) for all Android phones.