Do not assume that the LISTING PRICE is set in stone!!!
Have your Realtor do a CMA to determine Market Value.
Have your Realtor include Contingencies for Loan (more than 17 days), Inspection and Appraisal.
Do your Inspections; don't worry about hanging the costs on the Sellers; too small and you want to own the Inspections.
Don't worry about hanging the Closing Costs on them, they would just inflate the Selling price to cover.
You can certainly negotiate Your Interest Rate with your Lender; a 1/4 point will make a BIG difference. Talk to more than one Lender.
good luck and may God bless