My goal is to have 6 multi units in 5 year span.

Most product life-spans can be predicted.

After running numbers and consulting with AirDNA, which I would Highly Recommend when evaluating short term rental revenues in your area, we found that over a 12 month span we should average over $3,000/month going this route, putting our out of pocket around $1,400/month before expenses.Our long term plans, depending on how the market goes, are to live in the property for around 2 years, refinance out of FHA to drop the MIP, and rent both units out as short term rentals.  

They span the range of investing types, etc...  

typically shingles will run you $20/bundle (3 per 100 sq ft or 1 Square) for lower end, install depends much on tear off and prep or shingle over and prep, we have opted for Steel when ever reasonable to do so, it costs about 10-20% more up front, but will out last me, and does not have Ice damming problems we see with regular shingles in the north. standard shingles, you can expect about 1/2-2/3 the stated warranty actual life span, so 40 year shingles will last about 20 years, but steel, even 40 year has been known to far exceed the 40 year warranty, I can typically get a roof done in steel with a 2 layer tear off, and steel installed for around $4-6K for a 13 Sq roof thats material, labor and disposal, I just has a 11 sq one does with dimensional shingles (steel wasnt practical) for $2,700 including tear off and disposal. keep in mind, the cheap guy may not be the best value, there are a lot of hacks out there, and anyone with a pitch fork, a hammer and a nail gun calls them self a roofer. 

All costs are added up during it's 30 years life span and averaged out to be represented by a statistically accurate percentage estimate.

My primary focus is buying/selling notes, but I was contacted by a homeowner in the Mansfield, Ohio area who is selling his house on a land contract and doesn't have confidence that his tenant/buyer will be able to buy the house when the contract is up next September.The T/B has been in the house for 3.5 years, but has been late with payments (which are just enough to cover the mortgage) several times over that span and the owner believes he has grounds to cancel the contract.

The property is in decent shape structurally, I will be putting another layer of shingles over the roof (one layer currently about to end of life span), Exterior needs a fresh coat of paint also.

On the financing end we've been subject to FHA's self sufficiency rule for as far as time spanned but recently in early 2016 they (HUD/FHA) changed their 100% income SS rule to be more realistic and added a 25% discount for repairs and maintenance + vacancy.

I do understand that these strategies span the gamut of totally active to totally passive participation.