I'm gonna be home tomorrow, which is when I'll be available to post and shiet
At any rate, some issues beforehand:
Though Artemis would be analytical and able to deduce the little details out of whatever is being observed from being an expert with technology (as well as tons of numbers and all of that computer stuff), I do not think that she would instantly recognize that it is the same person who put a gun to her head since in those posts, she did not even look at him once, and the only recognizable feature would be his hair, though it is styled in a different way than before. His clothing is completely different, his eye color is different, and his tone of voice is more American (to obviously fit the persona he is donning).
Now, it may be pure coincidence that she would recognize him through his voice, but given that his tone is different from the nonchalant and sarcastic way it was in their previous interaction compared to now which is Fionn-like in an American accent, as well as how brief their interaction was, it's unlikely that she could just know it's him.