Lastly is structures, and to be honest I think we'd probably have to move the needle $100k or so on that item because I have a feeling from what I've seen thus far is these structures are not of the most durable enduring type and I will have some considerable cap-x over 10yr window on them.

I run sum numbers for you please see comments below before refinancing and post refinancing .If I were in your position, I would approach it as follows:Initial Investment Assumptions: Market Value: $360,000 Purchase Price: $360,000 Equity: $0,000Financial Breakdown: Hard Money Loan (LTV 100%): $360,000 Interest Rate: 10% (30-Year Amortization) Monthly Payment: $1,995Upfront Costs: Origination fee (1%): $3,600 Closing Costs (3%): $10,800 Renovation Costs: $10,000 2 Month of Carrying Costs During Renovation: $5,390Total Upfront Required: $29,790Total Capital InvestmentPurchased price $360,000 Upfront Costs $29,790Total: $389,790To make this investment work, you need to rent the whole property for at least $3,165/month, refinance it let say after one year with 5% interest with a traditional mortgage.Year One Rent: Monthly Rent Income: $3,165 Monthly Rent Losses during renovations (2 Months): -$6,330 (-$527/month distributed over 12 months) Total Rent Income: $31,650 per year => $ 2,638 per monthMonthly Expenses: Hard Money Loan Payment (10% Interest): $1,995 / per month interest only Property Tax (Assuming $3,000/year): $250 per month Property Insurance (Assumption): $100 per month Utilities (Hydro, Gas, Water): $292 per month Assuming 0% Vacancy first year Assuming 0 % Repairs & Maintenance first year because unit has been recently renovated Total Monthly Expenses: $2,637Monthly Net Cash Flow: $1Post-Renovation Refinancing Strategy:So far, we’ve purchased the property, completed renovations, and rented it out.Next, you can approach the bank for a refinance to consolidate your initial investment of $29,790 plus your 360k debt into a mortgage.

@Mike Dymski, in my experience raising institutional capital early in my career, I would disagree about "following a sponsor" for years, and actually many of the deal level analytics (a majority of institutional investors invest in funds not deals), but your point is generally correct.Ultimately, what I see a lot on these forums is that a lot of people are relying on the investment manager to also educate them on macro economic conditions, which will always carry a natural bias towards their types of offerings.  

Clean it up a bit to get most bang for the buck add ons and preventative damage items like water leaks.

Admittedly, pricing will often account for any major items, and I don't believe this is true in Sandy Springs, but there are some areas that an interstate cuts off a small part of the neighborhood, and so labeling the neighborhood as "good" may be true for 90% of that neighborhood, but if you are in the 10% that is on the "wrong side" of the interstate, it can be a totally different market.

Plus you still have to actually underwrite the entire deal (purchase, construction, carry, etc to develop accurate CF/profit).

Alternatively, are there some ballpark estimates for each expense item (e.g., 8% for vacancy, 3% for capex, etc.) that can be factored in as realistic or worst case scenarios when analyzing the deal?

If this were my deal the sale price on a triplex would likely be around $900k, so if I bought the land for $150k, and my build costs were about $500k, I would expect my interest and carrying costs to be about 10-12% of the total of that, so lets say $75k, for all in expenses of about $725k. 

Yet, you should never say never and any investment carries a certain degree of risk.

An individual carrying back the sale of their home (owner occupied) won't be held to higher institutional standards, RE operators.investors may be being in the business.