They have a HELOC of ~$60kNumbers:Comps suggest ~$199.5/sqft (max 2,020 sqft)Estimated ARV: $335k (based on comps)Potential rent: $1,975-$2,000/monthQuestion: Do these numbers seem reasonable for the Braselton market?

Before being approached to help with the development costs, I had considered on buying after the development was complete; 4 lots then having 4 homes built, selling 2 and keeping the other two to rent out.

Property taxes and insurance are typically the two biggest recurring costs.

I'm wondering if the insurance costs are hiking up the expenses.

No the rates are not on par with conventional when you figure in additional costs and pre-payment penalties. 

In addition tenant flips take work and have costs.  

Realistically, if rents can't keep up with costs over the longer term, fewer people will buy rentals and there will be fewer options for those who can't afford to or choose not to own a home.

Our approach for implementation is to break all repairs into 4 categories by priority:1) Health & Safety - most important as could result in tenant lawsuit2) Property Preservation & Government Requirements - don't ignore a roof leak that costs hundreds to fix now, but will costs thousands in the future.

I agree with Maya I would use that to potentially house more guests. 

Rarely happens, but it's a potential outcome.