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

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

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

It is common for PMs to stick fees into paragraphs throughout the agreement, this is another red flag.

It was common back in the day.

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.

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

Just simple common sense. 

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.