Construction (brick or CB bldg will cost more to rebuild so you will need to have higher limits than a Frame building10. loss history of the property11.

He told me in 2019 to move forward and rebuild my business, so here I am.  

Insurance will cover the cost of rebuilding.

So, even if your insurance rebuilds your property, there might not be anyone to rent it.

The rebuilding cost will be higher for Brick vs Frame. 

For one small Northwest example, take a drive through the Detroit Lake Reservoir area between Bend and Salem, Oregon (an area the drains into the Willamette River which feed the Willamette valley and drains into the Columbia River) and drive past the scorched out Fire Truck and rural communities rebuilding after being burnt off the face of the earth.

They may be able to point out issues for that property (zoning issues on a rebuild, quality of local schools, encroaching commercial development, etc.) that impact the long term value.I would also recommend running the property by an independent Insurance agent to see if there are any issues that will impact the insurability of the house (knob & tube wires, fuses, age of roof, in ground tank, tenant dog breed, pool, etc.). 

I've been around a while so I understand that when prices drop, they can drop quickly and takes years to rebuild in inflated dollars. 4.

Once in how many years do I have to rebuild the retention wall?

Some Million dollar properties would need to be torn down to rebuild with the correct cash flow for long term holding.