You need to factor in variables like landlord insurance; are any of the properties in a flood zone - financed properties will require flood insurance; what is the age/condition of the houses and how much deferred maintenance are you going to have to perform; what are the property taxes going to amount to; a house purchased for cash will have less up front closing costs (no appraisal required, no inspection required) is that a factor in your purchase price; etc. etc.If you leverage yourself to the hilt, and you have no options for deferred maintenance and they do not cash flow (despite gross rents), then you have NO flexibility.  

This bracket is evaluated on the basis of a general expertise of the quality of the building: Ages, condition, infrastructure, maintenance, etc..

I put in my leases that if the appliances stop working because of age or routine use I will fix or replace, but if there are signs of abuse it will be the tenant's responsibility.

@Woods PeppermanKeeping or flipping is entirely different filter/glasses.A keeper would be something that matched my size, age,area, schools, price, rent, cashflow, and ROI pre-set criteria.

At my young age, how can I make a big investment purchase, with a strong plan, if I dont have 20% to put down on a 350k complex?

When scheduling a showing with a potential tenant, or during the showing, is it ok to ask the potential tenant the age of their children (if applicable)?

Some sellers just pass on these hot potatoes, having milked the property by keeping all the rents and not plowing much back into it...Then the exit strategy is to sell to someone who may not recognize all the deferred capital expenses.Some ideas for avoiding the hot potatoes (where everything is at or near the end of its useful like) might be looking at age (but it sounds like most listings are a bit older), so you might only look at those properties with updated major systems and components (HVAC, plumbing, roof, windows, insulation etc). 

We are aware of the lead paint issues that come with a home of this age, but planned on handling it ourselves.  

Also, my parents are reaching retirement age and don't have much savings built up.

Out of all my friends in my age group(34) I would estimate that we are slightly above average here in the Midwest.