Hi Eve, congrats! As others have said, it is not true that baby bunnies are easier to train, quite the opposite. It is also impossible to know what their personalities will be like when they are that young. Do not introduce a 4th bunny, that could upset the existing bond. Never go to breeders for advice. What they said about pregnancy is pure nonsense. And please don't breed. There are so many thousands of bunnies in rescue centres looking for a good home... Best to get the female spayed at 16 weeks before she gets hormonal as that could result in fights. And yes, it is possible the ears will still drop, they are still very young.