The investor who owns the property across the street is also developing but his property is zoned correctly already; his property is similar is shape and size.

Screening standards also have an effect on longevity.

This type of stuff happens but thankfully with good screening, it isn't common. 

Another less-ideal factor is that if I buy these on one loan (as may be necessary to meet minimum deal size) then I will have them forever linked, even after I refinance, unless I pay off the loan.

Maybe a tiny shed or something similar but no full size buildings. 

Screening them will be the hard part. 

Go to NETWORK at the top of your screen and you can search for other investors and investment groups in your area.

But since I don’t know what city you live in, you might need to ask yourself real quick, if the market size and activity level could sustain some ups and downs, especially since both you and your girlfriend are agents.

Wondering what the best online application system is for tenant screening?

Keep in mind that the cost of borrowing $100k more is in the neighborhood of $500/month and your neighborhoods, parking and size of the property and building change as well which changes the $$$$ you can make.