Several reasons to rent to own prior to financing:  1 tax code, you can only take installment sale tax treatment of seller financed sale if the property was an investment (rental), 2nd is long term cap gains, 3rd is check out the tenant for reliable payer...  

Contract for deed / land contract / installment sales - any of those actually creates an "owner" as well as occupant; used to be that one of those arrangements would be used and structured so that the occupant never completely fulfills, so in the end the deed stays with the grantor / previous owner.

The penalty is really designed for big businesses like Home Depot who have thousands of independent carpet installers, ect.

I hear this can cause legal complications for the landlord if he installs them.

That's no reason to spend more money on redesign, how about better signage?  

(including pro installation).  

Instead of going the multi-unit route, I got into financing through lease options and instalment sales.

I have been told FEMA will re-designate this area as 4E.I can't find the appropriate  description of requirements  for either of these zones. 

Tenants might install water beds, etc.Ask what kinds of rents policies you should require of your renters.

It's not just redesigning the roof, it's beefing up lower walls, adding floor joists in the upper floors,  etc. to handle the new loads.