My toddler sims sleep well. I usually have a family member put them in the crib at around 10pm. They might not sleep for a while but they are well fed and happy and don't fuss before they fall asleep. They generally wake a little before 6 and are happy to wait until 6 when their parents wake up. I am very strict about my sims' bedtime so there is no chance of a family member disturbing a toddler during the night. I find feeding the toddler just before putting them down ensures they last the night without getting hungry. I don't use any of the premium toys that fill the energy bar because they throw out my sims' sleep schedule.