If you say so (well, if you consider 29/30k close to 35k then yes).
Not a chance in the world. Even Metallica had to wait more than a decade to do that turnout.
Maiden biggest headline show is 69k. Maiden's record in Greece is Rockwave 2018 and it was 40/45k. Even if somehow they could surpass that, there is no way they can do 80k+ there.
It's not being "a negative troll", it's just knowledge of how sales work. Again, nothing wrong with the sales in Athens, which are by far their best for an headline show in the country, but there is no point in saying they could've sell out the entire capacity or that they could do 40/50k. One can easily monitor the sales for Athens.