The price of the property would not exceed the cash coming from the stranger's account + possible cash coming from my account.

Many properties sold very high for the potential risk.

Utilize Meetup.com or Eventbrite for real estate investing groups, BiggerPockets forums, CTPOA, and local events to connect with landlords, agents, and property managers.

The property is a 6bed 2 bath duplex.

New construction has a very different risk profile from buying existing properties and fixing them up. 

I'm also in the Seacoast region (NH and ME) and own some rental property nearby, so I know these markets well.

If your fee is $150k I would expect a very healthy budget to be spent to marketing and advertising this property all over the place.  

Search by property address: Use the property address to find the owner's details in the property records.

On commercial loans, it is not uncommon to see 25 year terms or balloons in 5-10 years.  

@Sequoiah BriseñoCalifornia multifamily sale and 1031 exchange purchases mandate landlords or property owners to issue 1099s for payments of $600 or more to a sole proprietor, LLC, or partnership, and request a W-9 from each vendor by January 31.Good Luck!