Anyone requiring that kind of "deposit" should at the very least have a presence online.

David,As it was mentioned, it all falls into math between lower interest (but presence of MI) on FHA loan vs ROI on 16.5% down payment saved as a result of not going conventional with 20% down.  

Is there a strong commercial presence?

Red flags will differ by investor as one person might not care as much about having to replace plumbing as another, but you should keep an eye out for sloping floors, bad/outdated electrical, plumbing, HVAC, presence of mold, foundation/retaining wall cracks, water damage in the ceilings, and there's probably a few more things but it will differ by location as basements and attics are not things I'd have to worry about in PHX, and scorpions north/south sun exposure are not things you'd probably have to worry about in NY.

And speaking of paint, yes, you would need to have every tenant sign a lead paint addendum, aknowledging it's possible presence.  

Look up the owner on county records or go post your services where park owners frequently occupy their online presence.  

You should have an exit walk thru in their presence and make note of all the issues you've shown above. 

Seems to be an active FB presence for Western MA.

I didn't realize the extent of the government's presence in Huntsville

If he is a Realtor® then he needs to disclose to you the presence of a valid Exclusive Right to Sell, but more specifically ANY COOPERATION.It is NOT a guarantee that because it is listed that there is cooperation.