Is this best site for searching for investment properties?

I also question the legitimacy of sites such as neighborhoodscout in their altruism as you are required to purchase a subscription for access to their information.

Lots of pictures on a web site?  

Also, what are some of the things that one could do to perform due diligence before investing in this sort of crowd funding site?

You will see this sometimes when there are known issues and the seller doesn't have the resources or the "mental strength" to deal with the process anymore.If you want to proceed further, make sure you speak to your lawyer about what's needed.

How do sites like zillow know what i paid for a downpayment?

Look at the map view of some realtor/mls type sites and you should see all the names I'm mentioning here.Also, through BP, I found a great realtor up there.  

I suppose you could get one from one of those legal sites, or you can get attorney to draft you one.

Ultimately, you may need to have some serious work done, but you can shop around for someone who is rated well on angieslist or other resources.

Another way is pay attention to signs or houses that have been purchased in your area and try to find out the owners or go to the job site to speak with the boss/manager for that particular job.