I feel for the artists whose job it is to draw and organize nearly 4000 little vector images, most of which will barely ever be used to communicate anything. I'm going to imagine that it's functionally impossible to make a font with full emoji support now unless you're a massive corporation. (Not that it's an issue really, but there's only so far you can push the list of required code points right? You can leave off…
These are all handcrafted, and some are quite original, e.g. when you combine one with itself. An entire team of artists must have worked on this for quite some time.