The ferret and the rats as archtypes. yes the ferret is a symbol of a sneaky animal and the rat, well in the catalog of universal archtypes is nothing good.
But there are personal archetypes which may override the universal. So if you think of rats as fun and loving pets-same for the ferret, then these animals may have a personal meaning for you which would be expressed in your dreams.
In my original post I wondered what dreaming of a loving pet ferret meant. After reading up my new opinion is that in my dream it symbolized that I was up to something sneaky but that I loved doing it. The same for the loving pet rats. I may have been up to something 'ratty' -in the opinion of 'good' folks- but that too I took great enjoyment in. Won't go into what those things were. Nothing illegal but had the power to hurt someone if discovered.