A: Not quite. If you Zap a Creeper, you would simply then place it in front of you. You don’t get to draw anything.
The reason the Creeper card includes the words “then draw to replace” is that if you draw a Creeper, it goes down in front of you, and that doesn’t count as one of your draws (or one of your plays) so you still have a draw left, which you get to execute. Or if you were dealt a Creeper at the beginning of the game, it needs to go down in front of you, and you need to replace the card missing from your initial hand, since you should not start the game with a smaller hand than everyone else.
If you gain a Creeper any other way, you just gain it. It cannot ever really go into your hand, so it goes directly into play. If you choose to Zap a Creeper, you just get that Creeper. The reason is that Zap isn’t meant to give you an extra card in your hand so much as it is meant to give you whatever card you Zapped. So it’s not like you somehow missed out on the card Zap was intended to give you, such that you need to draw to “replace” anything.