Is this "h-" what is called antilenition in technical/phonological terms?
Are Caite and cait (sorry, no strac on this keyboard) variant spellings or different forms? The pick list for this question has cait but the Translation has caite?
In short: Yes.
In long: https://www.foramnagaidhlig.net/foram/viewtopic.php?t=3269#p23658
How do we know when to use h-? This is the first time I've encountered it in the course.
Like with other mutations to initial sounds of words, it is introduced in the tips and notes.
Here the plural article na prefixes h- to nouns beginning in a vowel. The same does the genitive feminine article (eg. na h-Alba of Scotland).
Eich is mute on this exercise