Just FYI: night time dryness or nap time dryness, is not something attained, biologically, until even 7 years old. And is normal. It is about the body's organ maturity. Not the child.
For pooping, well I rather have my son just poop, instead of holding it in and getting Constipated. Because, Constipation is something very hard to remedy, once a child is on purpose, "withholding' their poop. I know, that happened to my daughter and we then had to take her to a Pediatric Gastroenterologist, because it then became a medical problem.
HE said, to just let a child poop, even if in a diaper. Because, once they start to 'withhold' their poop, or stop pooping all together, then that is a real, medical and emotion based problem.
HE said, a child will get there. But just let them poop.
It will fluctuate. And various things affects a child and their vacillating of it.