Wellness puppy kibble and lots of poop

Hello

Newbie here, also newbie to the dog world.

We got our Coton DeTulear one month ago. 4 months old. The breeder sent her with a quart of mixed kibble. She mixes her dogs food with Wellness, Chicken Soup and Nutro. We slowly weened her to Blue Buffalo small breed puppy. We noticed she refuses to eat the black nutrient pellets. We picked up a bag of Wellness puppy and are mixing. Started with 25% Wellness to now 1/2 and 1/2. She is constantly pooping. Pooped in her crate the last two nights. Something that never happened. I understand that not all foods will work for all dogs. I like everything I read about Wellness as was looking forward to moving her up to Wellness Core as an adult. I am looking to see what others have experienced and if I just need to stick it out until her tummy adjusts. Last night I slept on the couch next to her so I would hear if she needed to go out. She is very quiet and mellow. The first 3 nights she barked around 3am to be taken out and after that slept from midnight (when I get home from work) till 7am. I am also worried because we crate her at night and she has done well with me going up to bed after putting her in that if I start sleeping on the couch to make sure I get her out before pooping in the crate I will teach her that I will be there all night.

Confused
Cindy
TIA