A: Yes. Since everything happens instantly in Fluxx, Draw 3 Play 2 Of Them suddenly becomes Draw 4 Play 3 Of Them. The player should immediately draw an extra card and add it to the remainder of the cards being chosen from (the mini hand for the Action, not the set-aside main hand). It’s kind of like if you’d only drawn 2 cards instead of the 3 you were supposed to, realizing the mistake after playing one of them, and drawing the extra card you need at that point.
Of course, your regular hand will also need an extra card, since the Draw Rule itself has also incremented. You could do that at the time you’re executing your D3P2 by drawing a card and adding it to your set-aside hand, or you could catch up with that when you pick your regular hand back up again after the action. Note you’ll also have an extra Play to execute as well.
Adventure Time includes the Inflation analogue, Mathematical! Inflation is also available as a promo card to add to any Fluxx deck.
Math Fluxx includes a card called Increment All, which is similar to Inflation except it only affects Actions and New Rules.
Drinking Fluxx includes a card called Double Vision, which is similar to Inflation, but only changes 1 to 2, without affecting any higher numbers, so actually, it won’t affect Draw 3 Play 2, but it’s worth noting.