Your idea sounds interesting! I heard about your interests from my good colleague Cariad Astles.
I have been using puppets and soft toys in bedside theatre performances for children in hospitals since 2007. You might have come across my book (2016)?... As i say in my book my research reveals that children connect with puppets during performance. They often use their own soft toys and dolls to communicate with the actor through them. I am suspecting that children may be projecting on their dolls/puppets during performance...I am currently leading the 'Bird Island' project at Birmingham Children Hospital (cardiac, oncology, complex care, haemoglobin and dialysis wards) NHS, and Heartlands hospital paediatrics, Heart of England NHS. My actors use 'living' (child size) puppets in their storytelling.You might find this page useful: https://newman.ac.uk/knowledge-base/cadlab/
I would love to find out more about your research. I am looking forward to hearing from you.