Have you joined the 2017 Secret Cthanta yet?
1. When a card indicates zombie dogs (i.e. populate the pet cemetary with zombie dogs...)and there are no zombie dogs left in the supply, but there are normal zombies: A. Can you use normal zombies instead? and B. Should you use normal zombies but use them like dogs (i.e. half-heart and 5,6 to hit)? We went back and forth on these with no real resolution.
I don't think there would be an official answer to this. Now that you know the problem could come up you could make an agreement before the game starts. I think if I did place a zombie, I'd make it a normal zombie just so there isn't confusion later. You could also consider swapping out dead zombies (of either type) for some sort of marker or you could buy an additional bag of dogs.
2. Your character just expended his last heart token. Is he dead at that moment, or is he dead on his next lost roll?
The official rules say you're dead when you run out of heart tokens. I've seen many people play (and explain) the game as "a heart buys you a reroll", but that's not really what the rules say. I don't think it makes a substantial difference in game play, so I'd say whatever your group agrees on would be good.