How does Ubuntu Touch render emoji? Does it use the CBDT/CBLC color font format (like NotoColorEmoji.ttf from Android) or SVG in Open Type font format (like the EmojiOne Color SVGinOT Font)?
EDIT: it looks like it uses the CBDT/CBLC color font format like Android. This poses an aditional challenge, license wise when the world moves on to Unicode 10, since EmojiOne is no longer free. Hopefully by then there are libre alternatives (that aren't the horrible Android O emoji). I also hope to have the time to contribute to this, but CBDT/CBLC fonts are harder to compile than SVGinOT fonts, for what I've seen.
The Noto Emoji project is Apache 2.0 for the color emoji. If Ubuntu Touch uses SVGinOT Fonts, it's perfectly possible to fork Noto Emoji and convert it to SVGinOT and still retain the license (the B&W emoji are rendered on the fly from the color ones while compiling the font file). If the Apache 2.0 license is suitable for you guys, I don't mind setting up a repo to provide the SVGinOT font with Google's blob emoji from Android 4.4 while being Unicode 9 compilant (for the most part, because country flags and the rainbow flag (at least) are currently missing from the Noto project: I hope google updates it in the short term though, hopefully before updating to the horrible Android O design).
Another thing to take into account for Emojitwo is the transition to Unicode 10 and beyond. In the case of the Noto project, Google provides the updates under the Apache 2.0 License (which can be adapted afterwards), while in the case of Emojitwo those updates will have to be designed from the ground up, since they can't be forked from future updates of EmojiOne anymore).