It's basically a legal 2-unit that can cashflow $900/month.

I would like to acquire a 15 unit or so apartment.

That isn't written somewhere specifically that way, but your lender will ask why you would move your primary from (for example) a 2,000 SF SFR to a 750 SF unit in a four plex? 

If I had to guess I would say your money could “develop” 1-2 houses in Staten Island but in the right market you could easily get up to 12 or possibly more good units fully paid for.

You should consider getting the most units (that can rent for the highest) for the best price.

@Albert Gallucci as many have pointed out, in the commercial space of 100+ apartment buildings and offices, property classes have some pretty decent industry standards.We started applying these to 1-4 unit properties around 10 years ago, which you can verify on our blogs, because we saw too many newbie investors not properly taking into account things like, neighborhood status, tenant pool, property condition, etc.Unfortunately, there's no industry standard for this, but you can use some basic logic to think your way through your own Classifications.

Investment Info:Small multi-family (2-4 units) buy & hold investment.

Exclude any units that are out of your league and focus on similar comps. 

This criteria is for 1-4 and 5-8 unit programs.

Are the comps from the Bigger Pockets per unit figures?