Ideas
I am reposting this for those that don't read through the whole thread. Also, make sure that before entering CAS, make sure you have testingcheats on and cas.fulleditmode
In cas by the check mark and X is a little dice button and to the left of the dice button is a little arrow button. Click the little arrow button and make it so that it will not randomize anything except pet clothes. Then click the dice button. it will put some outfit or whatever on your pet but that is ok for now. It should also set the pet breed as mixed or allow you to select one, but I think it will just set it as mixed. Then you can remove the clothes or select the clothes you want on your pet and save. So far this method has worked for me with no worry as to changing the look of my pet.