Okay! So here's all the info I can give that resulted in a snow white bo for me.

11/15 Doman Plum's resulted in the "new feathers" message
6/6 Cieldalaes Pineapples resulted in the "new feathers" message
12/12 Valfruit Resulted in the "new feathers" message
Stable: Good

I didn't mix with the order of feeding fruits, just one at a time of the 15 Plums until I was out, then one at a time of the 6 Pineapples, then one at a time of the 12 Valfruit.