The goal/strategy is to find properties in the Philly area that could be rented out and generate cash flow. 

I was looking at Dover/Portsmouth for a small one family but am a bit lost in terms of what to look for and what property in NH would generate the most income.

There is a wealth of information on this website for you

Build a website?

I would look them up on my county assessor's website and see if they actually even owned property. 

Is there any legal issue I would run into if I only kept scanned copies of leases electronically, or better yet, only had completely electronically generated and signed documents like real estate agents use?  

After completing the class, running background checks (DBPR tells you how to do on their website) and submitting your application to DBPR, DBPR will qualify you to test. 

Do it yourself pest control https://www.doyourownpestcontrol.com/index.html is great.They have recommended products for each pest on their website, and if you are still unsure call and ask them.  

Some websites like Angies list also lets you search for local companies and under the review section people post up their review, with the work that was done and the costs.

You could partner with reputable investors in your area, or use some of the crowd sourcing investment websites that are out there.