R19, plus, she was very young being diagnosed autistic, that's a bit of a rush. I know the new wave is to diagnose young, but a 1 1/2 years old is too young! The child is still developing. Most often, I come to find out that children who are diagnosed that young are misdiagnosed.
OP, if the child is school age, they should have an IEP. The Team (parents, school, and state mental health department) should be working for placement, if the child is not successful at home AND school.
I'm thinking this child does not appear to be able to benefit from counseling, they would probably try a few things like Applied Behavior Analysis or send in a behavior coach.
Feces smearing tend to occur in individuals with low IQs or who are mentally disturbed.
If this child is low functioning, I would also involved your state's regional center. They would be able to provide a behavior coach to the home.
Together, as a team, now meaning Regional Center, (if the child qualifies for their programs) there should be a plan to eliminate the behaviors.
The school would not necessarily be interested in the home behaviors. They are focusing on child's learning and functioning at school. However, the Regional Center and Mental Health would be, so you need to get them involved.
That would help this child and her family a lot.
If all else fail and EVERYONE agrees, then the school and your state's Mental Health agency would suggest residential placement.
Parents will be giving away some authority, but they will be involved as long as they stay part of the therapeutic process.
Residential placement is the last resort, and it's often a place no one wants to go. However, if it is best for the child then the girl's family, school, regional center, and mental health agency need to show that everything has been done for the child.