Check local regulations on maximum number of unrelated people living under 0ne roof. 

Make sure you know the regulations. 

There are a lot of other issues, but for you as the owner, the main one is usually do you have to have the current tenants out to build (no income) on to the existing property or are you going to do a knockdown new build?

Additionally, we are digging into BLS data to compare already existing data.

I am going through the regulations and restrictions in that place (not a closed community but there are some rules).

Looking for guidance on options. new builds aren't hard to finance and I would argue they are preferred to existing fix and flip loans, especially if you have experience. banks look at your experience, your builder's experience, loan structure, permits, etc you need to get an experienced builder familiar with advanced underwriting and negotiations with local, regional, and national lenders. in columbus we do ground up construction for clients at a 20% discount so they can BRRRR out of the new build with equity and we have pages and pages of data on what we build and why and it's all supported by market statistics. 

What type of interview do you do with existing tenant(s) to ask them about maintenance issues?

If you can't find an existing multifamily to pencil out try to identify something that you could add an ADU to or a larger single family home you can split into more than one unit using ADU rules.

I'm no appraiser but have plenty of fix and flips as well as new construction but IMO, it will be existing home. 

Can your existing box support the addition?