This theory is different from normal theories, as it's entirely based on the flakiness of the writers and their desperate attempts to redeem Ezra.
What if they try to act like Ezra was the one who pulled Aria, Emily, and Mona out of the fire? And that's why Ali's story suddenly contradicts Mona being positive Ali pulled them out. It doesn't make logical sense, plus why would he pull out Mona before Hanna, but seriously, I think they are going to try really hard in season 5 to make it look like he was more of a hero than a creepy, boring stalker, and this could be one of the ways they're going to try. I would be soooo mad if they did that just because they regret making their precious Ezra look bad. Was everything about that episode (4x24) not set up to redeem him? Who's to say that wasn't, too? Ugh.
Anyway, I thought of this recently, and I wanted to vent in advance about what a terrible move that would be. I would be more satisfied (logically) if a stranger saw the smoke and came running to their aid than I would be if Ezra pulled them out.