Are there any application rules (that relate to filling it out) that relate to mortgage lending that anyone can point me to. Are there federal regs? State laws (I'm in NY)? Or is it a matter of bank policy? thanks.

I would suggest looking at Regulation B. You will notice that an application can be taken orally or written. It depends on if you have the information sufficient to make the credit decision.

Look at data collection requirements in both Reg B (202.13)and Reg C. I also understand if you are an OCC bank there is additional data collection/recording you must do.

Mortgage Loan Prequalifications is a good resource from the FDIC, however keep in mind the changes in Reg. C that will affect prequalifications vs. preapprovals.