The difference is clear here. a and á have two distinct pronunciations, and the last vowel sound in this exercise is clearly not á.
Unfortunately, some speakers of Donegal Irish don't differentiate between a and á. If you've had the misfortune to learn Irish from someone who can't or won't teach you to hear the obvious difference between a and á, you might indeed mispronounce comhrá, but this speaker does not make this mistake, and is clearly not saying comhrá, because the last vowel in this recording is easily recognizable as a, not á.
I remember someone asking a similar question and it was answered but I forgot where I found it and so... yeah I'm going to ask again. :D Is "Is e..." used when the "it" has a definitive particle ("an") and "Is ... e" used when the "it" does not have a definitive particle? Because I remember back in Basics 1, there was "Is fear e" and sentences that use the "Is...e" instead of "Is e...".
That's the case, but remember the definite article [an] won't be there where there is a phrase in the genitive case: e.g. 'Is é namhaid an phobail é' = He's an enemy of the people; where the final é refers to him, and the first é is there because 'namhaid an phobail' is definite but in the genitive case, so loses the first 'an'.