If you don't mind, would you elaborate on what you saw in those toddlers that caused you to make those predictions?
I usually do much better with a specific case in front of me to answer such a question--and less well in the abstract. But I'll try . . .
1) Bottom line super key--REBELLION AND DEFIANCE. Keep in mind the adage--DISCIPLINE WITHOUT SUFFICIENT RELATIONSHIP PRODUCES REBELLION. And rebellion and defiance can be observed in the first month of life. If it's still winning out over the parents' wills by the 3-6th month of life and certainly by the 12th month of life, then the child is definitely headed for trouble. If it's still true by the 4th year of life, then the teen years will be hell on all the family.
2) Withdrawn, angry, enclosed, encased demeanors, actions. Now Autism and related problems are another ball park. I'm talking here about more or less physically etc. normal kids.
3) Obsessive people pleasers, super insecure, super manipulative, devious demeanors and actions.
4) Chronic lying, stealing, stubbornness, stubborn pouting relentlessly.
5) A certain look in the eye, spirit about the child that spells TROUBLE.
6) I'll note here--though I'll likely lose a number of you--IT IS VERY, RARE--used to be anyway--for children to be born with a serious demonic problem--whether oppressed or possessed. But it does happen. That sort of problem usually requires serious prayer and fasting on the part of the parents and some members of the church group. Usually, the parents are as rife with demonic problems as the children. That then requires a larger group effort or some comparable spiritual umph to deal with--even to get the parents free enough or listening to God enough to WANT to be free. BTW, I've even seen pets possessed. And the home was not free until either the pet was delivered or removed from the home--calamities still abounded until then. Stopped immediately afterward.
7) Extreme chronic apathy, vacantness, absent--rarely to never PRESENT.