I'm thinking about doing some experiments/studies on the personalities in Nintendogs + Cats, as I was reading an older blog post from Nurylon (I also saw that FourFlames had a blog post on the same thing back in 2020) which said they were unable to find a specific personality type with the dog they were looking for, and I've experienced the same thing before too, or at least a seemingly increased rarity for the personality type and dog combo I was looking for.
It could just be down to super unlucky RNG, but I've noticed it three different times now, so I'm thinking that the probability of getting specific personality types might depend on the breed and coat color (the personalities that were showing up frequently for me were different between sable & white and black & white Shelties, for example).
I won't be able to get any solid percentages for the likelihood of certain personalities as I have no way of accessing the game code, but I can definitely put together a list of which personalities seem to be more common with which dog breed/coat colors. I'd probably look into the difference between the available personalities for starter dogs and later on in the game when more personalities are unlocked too.
If my results are consistent (I have all three versions of the game so I will test it across all of them - I did see in FourFlames' blog post that they've already put together the info for Toy Poodle so I could complete the tables for French Bulldog & Golden Retriever if that's something y'all would be interested in), should there be a section on it in the personalities page?
It's super interesting to me so I'd be more than willing to help look into it more!