Given the high repairing cost, do you think it it is worth to upgrade all the house to this type of valves?     

And of course your area may be different in terms of cost and also some jobs don't require a full cosmetic renovation, but most of mine have.Then of course check the big ticket items like HVAC, roof, exterior siding/masonry repair, windows, interior sheetrock replacement, foundation and water heater and know approximately what it will cost to fix/replace each if warranted.  

I think the current tenant is paying close to half what the current market rent is and I need to make some repairs.

What repairs are needed?

@Adam L. welcome to BP, sounds like you already have a head start on the finance side of things.

Is the after repair vales (ARV or expected sales price) realistic?

I can paint, replace carpet and do minor repairs without a permit.

Sounds like you've got a solid plan for your REI strategy and your background at REIS will no doubt put you ahead of the game. 

also, I'm told after Tenants move out with Cats to do all the Remediation work, Remove all Carpets put down new flooring, repair and clean all surfaces including air ducts for heating and air. to call an Indoor Air quality inspector and get units certified as Allergen free.

I'm looking at a $2000 repair for the ceiling replacment and another $500 for the HVAC repairs bringing the total to $2500.