If there's only one card left and someone needs to draw 4 because of attack cards, what do I do? Do I draw put a defuse down and then draw again or what?
Attack cards force you to take extra turns, so it's not just "draw 4" but rather take 4 turns in a row, each one that will end with you drawing a card. So you should simply handle each draw separately. So yes, you would have to draw a card (which must be an exploding kitten because it's the only one left), and then play a defuse which allows you to return that card to the deck. But then it is still your turn, so you'd have to draw again.