Ezra is not A though, he was just following the girls that night and he found A's lair. He looked pissed cause he found out that "A" is still around (which he didn't know since last season).
The producers are just toying with us with implausible plots as usual. I mean how come CeCe just disappeared without any of them even hearing it?

And

at "Red Coat" suddenly being someone they should protect.