Best advice is to just relax. Give yourself extra time.
Contract √
50% deposit √
Scout the location √ (personally I rarely scout locations, unless I think its a difficult project).
Assistant booked √
The reality is on my first job I winged it. I had equipment insurance, but I did not have liability insurance yet. It is not my advice not to have insurance, but the reality if you only have 1 job 1 day sometime you have to do what you have to do. If they do ask, you might be able to get insurance and cancel after the project.