Hi Roger,
So, you are not seeking small-caps but how to enable some features on .otf (by the way, the font you uploaded is a .ttf, or not?). It's not possible for now to get what you want, at least, on epub. Nor property "font-variant-caps" nor property "font-feature-settings" will work, except "font-variant-caps: small-caps" (and with any font, not only with .otf with special features embbeded). Give a look to this pages:
https://sparanoid.com/lab/opentype-features/
https://sparanoid.com/lab/opentype-features/#c2sc
And there also you'll find the names of the .otf fonts that support the features you want, many of them are free. So, you can do your tests with them too.