Looking to invest in a few properties over the next 5-10 years and want to get a sense for tenants, common issues, etc.

I have doubts about his experience in RE, which I believe may be common among CFP. 

Does anyone know of a site or common place to meet investors and rehabbers to make a deal with.

I enjoy helping new investors avoid common pitfalls and use loopholes to build their REI portfolio.

Well said Jordan, it's not as common in this market to have an ADU but there are some out there.

However, these are the ones most commonly used:Five-of-Ten-Year Test: You must have materially participated in the activity for any five of the past ten years.500-Hour Test: You must have materially participated in the activity or activities for 500 hours in the current tax year.Step 3: Calculation your participation hoursEnsure you are tracking your participation hours.

Software is a common question on BiggerPockets.

Are these common now?

Looking at pure spreadsheet math and common convention; if you pay down your mortgage you are effectively making that interest rate on your money. 

It was common back in the day.