Copyright with special characters

Yes but if you were to copyright those characters or content for yourself it is almost certain to conflict with Apple's interests.

Merely incorporating them in a publication (academic or otherwise) is ok.

Where can I find copyright statement for these special characters?

Legal - Contact - Rights and Permissions - Apple

veramata wrote:

We are only using it for a publication. The editors ask us if we have the right to use these images. Is there some official statement regarding this that I can present to them?

Legal - Contact - Rights and Permissions - Apple

Note that emoji characters may not always appear exactly they way you see them on your Apple device. Other platforms have their own emoji fonts which may use somewhat different glyphs, e.g.

https://emojipedia.org/pistol/

I think the specific images from the Apple Color Emoji font would probably require Apple's permission for commercial use. Best ask them.