I have already been approved out of concept and have received comments back on the first submittal of SDP. 

I feel as though we miscalculated something.One unit yields $400 in rent (1 bedroom) and the other yields $800 (3 bedroom).Total Rent: $1,200Duplex Price: $67,000Down Payment: $3,350Repair Estimate: $2,000Closing Cost Estimate: $1,500Total Investment = $6,850We factored in:Mortgage: $340Mortgage insurance (we would have a low down payment): $40Home owners insurance: $67Property tax: $113Vacancy savings: $60CapEx: $60Repairs: $60Lawn/Snow: $120There are no HOA dues.Total costs: $860So, our monthly cash flow should be $340.Annual cash flow $4,080Total Investment $6,850ROI: 59.5%I feel like this return is far too high.Is there something obvious we're missing?

Unless you know that the property will be competitive and have a way of verifying other offers they receive that is a good way to get a counteroffer at $150,000. 

When you do sell reserved spots, do you include it in the lease or have it available as a monthly (or annual) add-on?

We looked into several scenarios: making a few loans at 10% vs one per year vs. buying a rental property (with and without leverage) and the administrator fees will eat 40-60% of net annual income.

One of them presented a new deal to me but I see there is an "origination fee" of 1.5% that goes to the managing partners of the LLC (they also are the property managers and take a 3% of gross as fee but only after 7% pref rate is returned annually).

This seems like a pretty easy answer to me, but the advice I received was pretty adamant I live in my 1st rental property even if it is a single family home.  

Doesn’t mean your brokerage can’t receive referral fees for clients though.

I am talking with quite a few homeowners at the moment but need to create/receive a wholesale contract that has an escape clause and such.

The seller has provided me with a 2013 appraisal that is quite thorough and has many comps and valuation approaches, but obviously is 5 years old.He also told me that they have a recent appraisal that was done and when I asked to see it, all I received was a couple of sentences that used the income valuation approach to come to the same price he originally offered.My main question is what value does the income valuation approach have to a property that could potentially be vacant in 3 years?