At what point do creatures entering the battlefield begin to be affected by enchantments and abilities of creatures already on the battlefield?
For example, Mentor of the Meek's ability triggers when creatures of power 2 or less enter the battlefield.
If I play a 2/2 creature while Honor of the Pure is in play does the Mentor's ability trigger?
Similarly if I play a 2/2 human creature while Mayor of Avabruck is in play (face up) does the Mentor's ability trigger? (It clearly has no effect if the card is transformed (face down) and the Mentor's ability would trigger.)