No, the would is not modifying time relationships. If it had "have", then it would:
You know what probably would have happened if I had fed the cat?
I think I drop the "had" sometimes in similar situations, but it might be a grammar error.
I'll take out the "have":
You know what would happen if I fed the cat?
Now we are talking about the future, you could say. We are using the continuous.
But it looks like you understand numbers 1 and 2