Answer: I helped someone out with something very very similar to this if you can show me a "model" I might be able to help you out because without the model I cant give you the answers to all.
I can tho, answer the 3rd and 4th questions so here.
Question 3.
When a Rock is completly melted into Magma, Change occurs because the magma that was once the rock will cool off and harden to eventually become a new layer of igneous rock.
Question 4.
YES! the stone that undergoes both physical and chemical Change,
Physical and Chemical: The Rock goes from a sturdy and hard substance to a magma which means the heat melted the rock and changed its physical form and the chemicals ALSO helped with that as it also changed the way it would deform and harden again.
That's all the help I can offer UNLESS you send a model or something similar, I helped with what I could Good Luck.
