Do I understand correctly that Keyman (mobile) can now display emoji button like other factory keyboard/Gboard? If so, how can I add/activate it. If there’s any new documentation available, please let me know.
Sadly, not yet… We’d probably build it as a custom keyboard… certainly doable but will take some effort.
Is there any prohibition to include such button in my keyboards? I envision not all emojis, but just some of the most frequently used. no more than 100 symbols, maybe even less than half of it.
No problem at all – you can certainly add emoji to your keyboard. The primary limitations will be that a good emoji picker really needs scrolling and support for skin tones and combining emoji etc but as a starting point it would be a lot better than nothing for users!
Or you could create a separate emoji keyboard which can be installed together with your keyboard, as another option?