What happened to gamma?
The way I calculate the three transformed events, I get:
A' = (0,0)
B' = (-0.577,1.1547)
C' = (1.1547,-0.577)
So A and C do not have the same time coordinates so they are not simultaneous.
EDIT: I see that wasn't your point. I should have said, the time between A and C is not the same as before, it's longer in the primed frame. But I wouldn't call that time dilation, it's just different coordinates for a pair of events.