That's my plan for the areas I can access. 3/4 of our basement is finished with drywall ceiling so I have to fix those from the topside.
I'm not sure about the laws in your state but here in Ontario if a basement has been finished and no permit was issued for the conversion then the new owner can apply to their title insurance to have the basement redone to insure it complies with the building codes. The squeaking floor fix could be thrown as a thank you buy the contractors for choosing them. I know some contractors who look at homes for sale to check on the basement and then head to check the permits issues for that house. If there was no permit they buy the house and are on the phone with the title insurance company and then they get one of their buddies to redo the basement.....