we're  pre-qualified for our next purchase but not sure if it should be another single family or multi family unit.

I live about 6 hours away from where my rental property is located and plann to invest in that area due to the price of single family units.For the no money down option for home purchase I'd look at VA loans if you qualify. 

If looking purely for investment purposes townhomes and single family homes zoned for short term rental are an option and may provide a more predictable occupancy profile provided it is properly managed. 

Or, if I'm completely mistaken and single units cant be purchased by multiple people then by all means, dont hesitate to label me a bafoon!

The market I am looking at is dominated by single family homes so that is what I am looking at. 

I also help investors buy and sell single and multi-family rental properties. 

Mostly small portfolios but some single purchases.  

Markets Chang and multi-family prpty are financed differently than single-family.  

As to a balloon payment here is what that basically means: you pay x dollars for x years and at a specified time any remaining balance is due in full as a single payment.

Depending on permitting, construction time and market conditions it could take you 5-6 years to get out of that single investment.