Been getting nowhere with zoning laws found online and in the local library for Yonkers (in westchester county) as to whether any permits are needed in order to operate such a business. 

I would go to the big bus tour events in Irvine CA. what was happening was there was a turnkey operator that was allowed to offer their product at the end of the Seminar ..

I think this is the first step so they can know who has the lead pipes before they pass a local ordinance to require the replacement at the property owner's expense.It's a "first registration, then confiscation", of sorts.

Then determine if a long distance property is better or a local house hack.

I would add that you should definitely checkout some local real estate meetups as that's the best way to quickly build a buyer's list. 

I’m going to consult a local financial planner but thought I’d ask the brilliant minds at BP as well.

If you check out their website, you can find a local Rep to come out and quote you on their products and help install.Most of ours were hard wired, with quick install, to avoid the internet issue.

Most of those specialty programs (first responder loans, downpayment assistance, etc) are based on local state/county grant programs that back the loan.

However, it’s important to ensure the area is safe. in those areas I would recommend checking local crime statistics on SpotCrime. you can use this link for an example,to get detailed information: https://spotcrime.com/map?

Check local law, whether you have to accept varies by state.