However you can install a couple of large footings at the end of each wall and install a beam, maybe a steel I bean into the ceiling and to which the cross ceiling joists connect using joist hangers.

On my latest rental, the water heater is original, installed in 1997 (contractor's grade, nothing special).

My broker does mid-century modern rehabs, new construction and consulting in Palm Springs and San Diego (focused mainly on the Point Loma area) and we find that having top quality installs is key but basing the cost of the project on what is selling in the area.

Rather than install new ones, you could save a bundle if you are willing to put in the work to paint.

. • Bans a TOS requirement related to the following: inspections; improvements or repairs; removing junk or debris; mowing or pruning; performance of maintenance or upkeep activities; weatherproofing; upgrading electrical systems; replacing or installing fixtures or other items; and actions relating to compliance with building codes or other property condition standards. • Existing TOS requirements are unenforceable. • Statewide TOS requirements could still be imposed. 

I’ve even installed two washer / dryer units in the basement for use by the tenants at no charge.I’m really trying to find a way to evaluate this deal before listing it for sale. 

You don't want to do any long term installment contract without an attorney, if you can find one to do one.The DOS and FHA regulations are anchored in federal law, not administrative "discipline" and administrative rulings carry the weight of federal law. 

We were hoping to save some money so that we could seperate the heating, currently there are a total of three gas meters, wanted to install a 4th and install furnace/hotwater-heater/reroute plumbing to seperate the heat.

Not only are they not custom, you could not even buy at home depot what the builder put in for allowances on items such as cabinets and countertops (unless you went with formica countertops and MDF cabinets), then to top it off they are charging almost $2000/LF for cabinet installation.

Read more about Sub-To and installment transactions in the forums, with any of them, a buyer needs to be in a position to exit by selling or refinancing at any time over the term of the contract.