One thing to add is that when you buy a new build, your PITI will likely not be factoring in the correct state tax number.

What further analysis should I be honing in on and key factors/metrics/info that may be providing inaccurate numbers?

Other most common factor: Family Size increases due to marriage or having a child. 

This concerns me about the potential to maintain a solid tenant base and would likely cause a higher vacancy factor.

They have a high hassle factor and he sold most of them.  

When considering refinancing, also factor in the closing costs of the new mortgage to determine if it actually helps you.

Insurance is just an expense to factor into your underwriting just like property taxes.

The house will need a new fence soon, so I'll have to factor that into the scenario.I'm not sure which choice is the best option for me.

There are at least a couple factors at play.  

Experienced managers can help evaluate potential investments by providing insights on rental demand, market rents, tenant preferences, and location-specific factors that affect leasing success.For example, rental properties need to be close to conveniences like major roads, shopping, and schools.