[css-inline] Should first/last baseline values of `vertical-align` belong to `alignment-baseline` or separate longhand?

Do we need to add first and last to [baseline values](https://drafts.csswg.org/css-inline/#transverse-alignment)? 

Note, in this property, these are combinatorial, whereas in the align/justify-self/content properties, it’s singular. Do we want to align the syntaxes wrt hyphens vs. spaces or what?