I am a contractor in Lubbock and just ran a model for 30 units (5 bldgs of 6 units) single story (this is popular in Lubbock) My cost to build was about $85-$90/sf (excluding the cost of land). 

All in at $63500(excluding closing costs)Apprasied $84500.

I'd say, arbitrarily, excluding the bottom quarter of the more crime-filled neighborhoods.

Here in El Segundo (near LAX) SFHs with 3/1 or 3/2 rent for about $2400-3200/mo which sounds great, but they cost about $800k to buy (excluding short sales if they come around).

Following are items generally not considered eligible compensation to fund IRAs.Earnings and profits from property and investments, such as rental income, interest income, and dividend incomeDeferred compensationIncome from a partnership for which an individual does not provide services that are a material income-producing factorAny amounts an individual excludes from income (other than combat pay), such as foreign earned income and housing costsRetirement income, including Social Security, pension, and annuity incomeDisability payWorker’s compensationUnemployment compensationChild support payments

For 1%, do you really want to exclude a good number of buyers from seeing your house?

We do NOT exclude those.

While my first preference would be a duplex (so I can learn how to landlord), I hardly find 5 duplexes on the MLS in the entire DC, Maryland, Virginia area (excluding SE D.C.).Are duplexes not usually listed on the MLS?

An accredited investor is an individual who makes greater than $200,000 per yearORHas a net worth over $1,000,000 excluding their personal residence.The link you provided is the most accurate to date.

I would think that mold would be excluded, as it wouldn't be a "sudden" event, and it would be your responsibility to dry up/remediate any water issues.