Your agent is describing a real gap. Most standard homeowners policies contain a vacancy clause that reduces or voids coverage once nobody's living in the house, often after 30 or 60 days, and some exclude vandalism and water damage first. The products people use instead are a vacant dwelling policy, which covers the building while it sits empty, and builders risk, which covers the structure plus materials on site during renovation work. Some carriers bundle them. Get the vacancy terms and the renovation exclusions confirmed in writing before you close, because a policy bound on the assumption that someone lives there is worse than no policy in an argument.
Separately you want general liability, since people who are not your employees will be walking through an active work site, and your hard money lender will almost certainly require coverage naming them and a minimum dwelling amount.
On licensing, whether an owner doing work on their own property needs a contractor license depends entirely on your state, and several states limit the owner-builder exemption to homes you actually intend to live in rather than resell. Your workers add a second question, because paying people to do the labor can pull in workers compensation requirements that also vary by state. Ask your state licensing board directly and get the answer in writing.
One more thing that catches first-timers: what you have to disclose to your buyer about work you did yourself, and about anything you found and didn't fix, is set by state law and differs a lot. Find your state's disclosure form early and read it before you start, not the week you list.
