Im not a legal expet by any stretch of he imagination but I would talk to the CFI.
If he confirms what you originally heard, write to him asking for clarification, allowing a reasonable period for his response. You want his comments in writing.
Maybe even talk to a legal person and seek advice first.
If you are unable to find any definitive info re seat loadings from the school, engineering etc, contact piper asking for clarification. Do Not offer them more info than they require. You simply want to know the max weight for each seat in a PA?? And any other pertinent limitations.
At the end of the day the school must have some liability towards your training costs if you are unable to complete it. You, in good faith placed yourself in the hands of this school, they should be aware of any limitations before taking your money, especially before 40 hrs. They cannot now simply wash their hands of you.