The babies will be fine with the adults. I mixed mine with no issues. What you have to consider though, is your baby snails may not get their fair share of foods with the adults. As they reach pea to dime size though, they become feistier.
I'll be interested to read this one. As far as my experience is concerned, the strange thing is my canas don't eat their own babies but any other species, are practically eaten, particularly my MTS, bladder snails and ramshorns. They still won't hesitate to eat a dead or dying snail which is even a member of their own species. The canaliculata complex is just very unusual in many ways.