Wouldn't this mean 'Are you going to call it?' (e.g. someone's name, or 'help!', 'fire!' etc)? Surely, 'Are you going to call him?' would be 'An bhfuil tú chun glaoch air?' - or am I missing something?
I would agree that "glaoch air" would seem more "normal", as far as my knowledge goes, for the translation of the English sentence.
See also this discussion.
Would "An bhfuil tú chun á ghlaoch" mean the same, something else, or would it simply be wrong?
I think that it would be wrong when chun (or le) is involved.
Should "Will you call him?" be accepted?
That means the same thing, but doesn't use the verb conjugation that this lesson is trying to teach, so I'd vote no.