The few cats with only front legs that I've seen featured on other forums have been incontinent because along with being born without legs, they were born with the lower part of their spine missing and also the nerves needed for bladder, and sometimes bowel, continence. The same goes when they lose their legs to an injury. Since nothing is said about this issue, I will assume that Miracle does have control.

Is Kate aiming to end up with no cats at all?