If there are issues with these items are these major red flags?

@James Walker I would start with planning and zoning, assuming you've done that part and/or feel likely you can get it approved, then I would pay for a feasibility study from a neutral 3rd party. 

Do you have zoning permits, building permits, utility approvals?

The zoning doesn't allow for more than two dwelling units per lot. 

And thats a red flag. 

There was a guy on BP who tried to get one going down by Colorado Springs awhile ago called Bonsai Village and got as far as buying the land, but could never get permission due to NIMBY neighbors  and it got stalled in legal red tape until the  land eventually ended up being foreclosed on and turned into open space.

My partner and I own land outright that is zoned for a single-family home in a new community. 

Hi All -A bill was recently passed to allow Accessory Dwelling Units (ADUs) (<900 SF) to be built by-right in single-family zoning districts.https://www.mass.gov/info-details/accessory-dwelling-unitsMy understanding is that you could buy a single family home and build an ADU on it and rent it out. 

What are the red flags and concerns?

In general you should start looking for a single family house that has zoning regulations that allows to ADU (Accessory Dwelling Unit) or can be setup to house hack.