But the plan is to sell it so I want to keep on working towards that. 

I get a Landlord policy and pay a higher rate while they are vacant.If you have major structural work to do then get builders risk insurance, otherwise just hire licensed and insured workers for cosmetic work.Without a Quiet Title you may not be able to refinance or sell the property to a buyer using financing.

4-5% is typical when buying and 9-10% is typical when selling.  

Save this post, because if you think you can find and manage Class C tenants from OOS, there's a VERY high chance you will end up being penny-wise, but dollar-foolish.Hopefully, you'll be able to recover from your mistakes & losses and won't have to sell at a loss.

This was one of the selling points for us.

If good it will sell in a day, Good luck 

We prefer to have tenants on yearly written leases, unless we are looking to sell the property or have other plans and may do extensions of 6 months and one day if tenants are planning to relocate, purchase a home, etc,  and cannot commit to a 12 month lease.

They are looking to sell and would be subject to FIRPTA tax. 

Would it be just as profitable to sell their building/land and not build?

Should we risk renting or just sell?