Rookledge calls those examples "Spur Serifs" and also includes Copperplate in the same group. RebeckaR is correct though, current classification places them in glyphic because they resemble carved letters.
One easy choice to make with many fonts that have an uncertain classification is to consider whether or not they're suitable for paragraph text. If not, just throw them into Headline and Display as a group.
Optima has curved terminals and strokes but does not have serifs. Most type people agree that Optima is a Sans Serif in the subcategory of Humanist.