"fuil" is the dependent form of "tá" - it is used for making a question an for negating a "tá" sentence:
"tá mé fuar" - "an bhfuil tú fuar" - "níl mé fuar" ("níl" is a contraction of "ní fhuil").
The verb in this sentence is "seachaid" (seachadann in the present tense), and the interrogative form of a present tense verb is created by adding the interrogative particle "an" in front of it (with eclipsis, if the verb can be eclipsed).
??? Why do you say "still"? Exercises that don't have audio don't have audio.
When the old audio recordings were replaced in April, 2016, some exercises that used to have audio didn't get new audio, and some exercises that didn't have audio before got new recordings. The comments were not updated.
That was a "one and done" change - there has been no indication that there will be any further changes in the available audio on exercises in the Irish course.