What questions should I ask for a commercial lease?

It depends on the terms of the lease. The apartment is not habitable at the moment, so you should at least get a rent abatement. You should have a Colorado attorney review the lease.

Much of that depends on the tenant and the agreement they are willing to enter into. Personally, I would want my tenants responsible for as much of the maintenance and upkeep of the property as possible. The same goes with the property taxes. You could calculate out what property taxes are / would be per square foot and allocate to them which will permit you to adjust rent annually to accomodate changes in the property taxes.

If your lease doesn't allow a sublease, you can't do it. I'd just approach the landlord and see what could be done. If the person moving in would be willing to sign a one-year lease and do the typical background check, the landlord may let you out of your lease.

I suppose it doesn't matter if you have the lease giving you permission and the lease is long enough to justify the building expense when you won't own it. But I'd buy the land so you could eventually sell the property with the building on it.

Did you purchase the property before or after the fire? If before, did you have insurance? If after, what was the agreement you had with respect to the insurance proceeds the Seller was to receive? The Warranty Deed is what is offered when there is a transfer of real estate and the seller warrants ownership to another. Frequently this will also involve title insurance to back up the warranty deed if there were other claims against the property