i'm going to have to have a company come rip up the drywall, dry everything out and re-drywall/paint....I imagine that whole process will take at least a week.The home is a 3br/2ba...their 2 children's rooms are unaffected and the couple in the master could move their bed/clothes to a "play" room downstairs or live in one of the two living rooms in the home.  

As far as The lead based paint I usually have one of my subcontractors that has his certification do the scraping and skim coating and prImer just to be on the safe sIde.

3 - How many times will you have to replace floors, kitchens, furnaces, HWH, driveways, porches, paint, bathrooms, roofs, etc...over those 10, 15, 30 year periods?...

I have been a property manager for 15+ years as well as know all trades (roofing, minor plumbing, minor electric, drywall, paint, carpentry) from my years of working on homes.

As a filipper my costs are a lot higher compared to a buy and hold investor.A flipper will put in new carpets, refinish the floors, paint the walls etc. etc.A buy and hold investor will NOT do any of that stuff.

The flip side however, is I've gotten new roofs, siding / painting, landscaping, etc... when it comes to external maintenance that was handled by the HOA.But what I'd caution you over even more than HOA fees, is the CCR's...

Is it likely that repairing this area, new flooring, new windows, new HVAC and paint will remedy the problem.

This duplex had some recent upgrades to flooring, painting, hot water heater, appliances, etc.

There is a house across the street from me that has the same major details (sq. ft, bed, bath, etc) that just sold for $138K so I am confident that there has been a good amount of appreciation to my home, not to mentioned that while I have lived here I have updated the kitchen, flooring, furnace, water heater, and paint to add to the value.

New plumbing, new metal roof, paint, flooring, vanities, countertops, furnaces, electrical, fixtures, outdoor lighting, new driveway, appliances.