Like I said I'm about a month of education away for starting an intensive search.  

It's also a lot more labor-intensive because you have to be constantly looking for, acquiring and flipping houses in order to keep it going.

Sure its more time intensive, however less capital up front.

Downsides would be commercial financing with adjustable rates and balloons (which you already have), the properties would have a smaller buyer pool and probably take longer to sell if you choose or need to, the tenant class may be a bit more management intensive for a similar location, and higher buy in price.

I wanted something less intense in design and get more exposure to the business side of things which I tend to really enjoy.I also wanted my job to be more in line with real estate which is why I recently started working for a small structural engineering firm focusing on residential projects and small commercial.

Are there any grounds for justifying/convincing the bank to treat this as a 5 unit apartment building as is the case for all intensive purposes?

I'm having the windows replaced (over 2 days) at this same place and it's way more labor intensive than framing a porch to make a room.

If it's a rougher area with low income tenants at 400 to 500 a door the collections are more intense, bookkeeping is heavier, more repairs and turnover and work to fill units.A nice area you could get for 50 units all in one spot about 5% to 6%.

. - Doing anything part of the project is tool-intensive.

That will generate very good cash flow.Vacation rental is also more management intensive. if you are planning to scale up, keep your investment simple.