your explanation, if you want to call them that, are basically all ‘it is not impossible, therefore it should work’ or ‘the players would enjoy it more if it worked’, these are not really explanations, they are justifications / excuses, not a strong case on the merits.
The closest one was your ‘the Dark Powers mess with the characters, so they believe they managed to reach their contact’, where it falls apart to me is that this was intended to actually work, without the DP interfering. Chances are the DP would interfere rather than just play the mailman