The number one thing we tell small business owners: your build-out timeline is a lease negotiation item. Ask your landlord for 30 days of free rent from lease signature to open. That's the pad you need for permits alone in most Chattanooga jurisdictions.
The second thing: unforeseen conditions are not force majeure. They're what you pay a general contractor to plan around. A good GC does a pre-lease walk with you and flags the ones that will bite.
The third thing: schedule your soft opening after your certificate of occupancy — not before, not the day of. Give yourself a week to walk the space, catch anything the punch list missed, and stock inventory.