Opentype features in webfonts are in their infancy (heck, they’re in their puberty on desktop!). For consistent results, you will need a different font file, in the same way you need one for small caps.
I'm sure this question must've been asked at some point, but I can't get the site search to work. Or maybe this is just a dumb question that no one else would dare ask ...
Is there a broadly supported way to specify figure style in a webfont via CSS? I'm specifically looking at Freight Sans at the moment and anticipating the client's irritation with text figures in price lines and other promotional uses. But a more global concern of mine is whether or not webfonts even address this need.