Wellness is a good brand, so I would stick to that. Her poops are a combo of the food, cookies and treats. I would think the liver treats may be a little rich, causing her to need to poop
Also, I think all dogs are different and I don't really think that 'better' kibble means less poop. When mine were pups, yes they pooped about 5 x a day.
Now they are almost 4 y/o - Roxy gets special food b/c of her liver issues, it's home cooked, human food, mostly veggies, fruit and cheese - WELL, she poops HUGE and I mean HUGE logs of poop 3 times a day
TJ is on a Raw food diet, he can also poop 3 times a day, but they are tiny little bitty poops, like cig. butts
I think she is ok with what you are doing, as she gets older, the amount of time will go down