You typically need a down payment for many things you buy.

Commercial Revenue Generating properties like office buildings, apartment buildings, retail centers, etc (banks call it "CRE" lending) are typically evaluated from their net operating income, not gross.

HUD targets average rents for an area, so just like average school grades, this typically translates to Class C property rents.In our Metro Detroit market, the MAJORITY of the claims about getting higher than market rents can be traced to a Class D Neighborhood/Property. 

We shall see but it may all be just typical yap yap.

We typically do 4-5 years interest only while paying down the principle balances over time.

I would echo @Brandon Croucier - the secondary market for DSCR's is super aggressive and rates typically reflect that.

No - absolute max for DSCR is 85% LTV and that is extremely rare and typically not workable in this rate environment anyways.Standard/common max is 80% (acquisition and rate-term refinances) and 75% Cash-Out Refis

Typically its done for open space or use for community property (ie. fire station location or other county use) and typicaly would assist in increasing tax base.  

Without accounting for management fees (I have not yet decided if I will try to self manage), and with planning to raise rents to typical market of $825 for each of the smaller units, and $1200 for the larger unit, does this seem like a worthy first investment? 

If the bank prices their debt based on the fed rate you typically see WSJ Prime + 1%.