Athelas font

There is, at least on my machine, something strange with the Athelas font. 

The Glyph panel shows for some figures: No Unicode, which may partly explain your problem.

It seems like a default font installed on my Mac, and when I look at the Font Details in the Document Info panel, it says:

Font Details:
Athelas-Regular

PostScript Name: Athelas-Regular

Mac Font Name: "Athelas"

Mac Font File: "/System/Library/Fonts/Helvetica.ttc"

Which is strange because it does not look like Helvetica and there is no Athelas to be found in that location.

Looking further there is a Supplemental folder that contains the font, which can of course not be removed without witchcraft.

Linear figures? Are you talking about the different number sets contained in the typeface? As far as I can tell they're all there (proportional lining, tabular lining, tabular old style, numerator figures, denominator figures, slashed zero and a whole bunch of pre-made fractions). Each style of Athleas has 841 glyphs and it looks like they're all there in the version hosted by Adobe Fonts.

IMHO, the Character palette in Illustrator is not as user friendly as it should be. The user has to click on additional fly out menus to access some character sets. Sometimes I hunt through the Glyphs palette instead. CorelDRAW was very late to the OpenType party, but I do like the feature where you can highlight a text string and click a down arrow to reveal a flyout of many OTF style options. Illustrator sort of does this, but to a far more limited degree.

Could you please post a screenshot of the issue?

Are the glyphs there in other software?