Checking in here on the off chance we have anyone who can answer some questions about insuring a commercial building while it is vacant/being renovated.

My service dog non-profit is buying an existing building for its new facility. There will be about 4 months of pre-construction work than up to 18 months of actual renovation/construction work to customize the building to our needs.

I had some questions about insuring the building during these times. Perhaps we have someone who is knowledgable?

Are you have this done by a general contractor or subcontracting the work out yourself?
My recollection from a few decades ago as a general, the building owner had their normal insurance. We as the g/c supplied them with a copy of our liability insurance and a policy called builders risk, and our sub's had liability insurance too.
All of this should be spec'ed out in each contract.