My friend had a client who nearly missed a crucial clause that let the syndicator raise additional capital from new investors, which would have watered down existing shares in a pinch.But it all comes down to how hands-on or hands-off you want to be.

That is if purchasing EXISTING performing investment real estate AND have very good clarity of every facet of the transaction ESPECIALLY reasoning for seller selling, AND you have decent market intelligence. 

Many times they do not realize the adding of the adu makes their existing unit rent controlled.  

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

Firstly, well done for persevering and trying every avenue you thought would get you the data you needed.Most would have caved earlier and handed out there hard earned cash for old, saturated leads/records from the same prominent platforms which dump them pretty much when they receive them from either 1).the same large brokers AFTER the county has listed them on the county website or, 2). from the counties themselves directly AFTER the county has listed them on there own website, or, 3). from data scrapers on Upwork/Fiverr who scrape the data from those same platforms AFTER the counties/brokers sell those platforms the data being scraped by the freelancers.Anyway, rant aside you seem to of made the same mistake i made when I first started branching out away from providing leads to my original couple of clients i got from Upwork who wanted me to scrape data from court records in FL for pre FC leads.Simply, I didn't know where to look for the information I needed in states outside of FL.FL only allows the judicial route to foreclosure so I only needed to know/find/scrape the data from Lis Pendens documents for counties they requested.

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

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

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. 

Can your existing box support the addition?

It varies, but when retainage exists that will drive up the cash to continue to advance the project because borrower won't be receiving draw releases equal to their outlay.