Personally, I’m of the view that Kanga had a thing going with Rabbit - or at least one of his friends or relations.
That rabbit is a shifty sort, just ask Owl.
Roo, of course, is completely oblivious to the situation - not in small part due to the fact that Rabbit has never sought custody of Roo - he just doesn’t seem fond of the little tacker.
The abiogenesis of stuffed animals is an imperfectly understood phenomenon. If I were to try and make sense of the relationships between the collection in MilliCal’s room, my head would explode. Better not to think about it.
It’s always been obvious to me that it’s Tigger. That’s where Roo gets his love of bouncing. Also, Tigger’s over there all the time spending quality time with the kid. He’s respectful to Kanga, she’s kind to him…it’s obvious that this was a one night stand kind of deal and while they both know it was a mistake, they’re working together to make the best of it.