A: No, it doesn’t mean they can be played as soon as drawn. You are absolutely right. All New Rules take instant effect.
The way this phrase came to be on only some New Rule cards is this: some other rules have helpful little subtitles about what sorts of Rules they replace, or a reminder that they’re Free Actions, and we wanted to have something consistent in that location on the layout so that all New Rules would have a similar feel. So we picked that “Takes instant effect,” although it doesn’t really mean anything more than what is true for all rules, as you’ve pointed out.
So it’s a little silly, but we hope at least that explanation makes it make more sense!