I think the sites and their estimates are pretty impressive considering they contain virtually every home in America, often with interior pics, but they are what they are: free tools that used automated formulas to predict something that can often be a bit unpredictable and can't fully account for the human emotional factor (for example I bet something like the Brady Bunch house zestimated far less than than its actual value)

Long-Term Strategy:We are predicting that the units will rent out for $2850-$2950 per month.

Often than "predictable", these things do not tell you when they need replacement. 

If they end up leaving the job after a year, renting in a house (+lease option) vs a traditional apartment doesn't make a difference, but they will have no way of predicting what the future will hold.

And this assumes that a very bad crash comes soon, AND you will be predict pretty accurately when to get back in the market.   

@Sameer Kh when you say it cash flowed $1200 last year, is that after accounting for CapEx, repairs, vacancy, and any other predictable expenses?

Do you factor in the 1% rule for initial asking price or for the ARV amount to predict cash flow?

Remember all the "experts" predicted disaster if Trump won the last election.

You may have heard this but location does matter and do not believe people that predict the future. 

People have been predicting and worrying about a real estate downturn since the last real estate downturn.