Your mind amazed me!
I kinda had a feeling when mr.cat and the friend met for the first time and he was saying that guy was a bad person and that he hurt him (talking about the incident where the friend forcefully confessed)... the only people who knew about it was winter who was growling, the MC who forgot everything, and the friend. So for Mr. Cat to know he had to be winter and with his hair turning white in the recent ep it seemed more plausible but it’s all my guesses
Also maybe he was reborn as a cat was because the friend was scared of cats.... they said he was scared of animals but he avoid the cats in front of the school and didn’t really avoid the dog so maybe he hated cats more .......
It's making sense now. Wow! Thank you!!
Maybe the friend who likes him was force ful with our MC and hurt him while doing the dog winter tried to protect the owner and got hurt or kicked so winter ended up hating the friend... and after winter died he was reborn by the cat god who also gave him a special power to turn into human..the white form is winter. Winter was worried about this owner being depressed after his death and wanted to continue to protect him from the abusive friend so he came back in another form.. he is a cat instead of a dog because it was a cat god that reincarnated him