The other very old school option is to just knock on doors, my first apartment appraisal thats how I collected rental data on competing complexes.

The sales and onboarding team (the team who collects your documents) are good, however, after they pass you to the actual property manager, it was very bad experience for me.

If I hired a PM that would also take care of collections (among other things) would I still need a service like rent redi?

I did better than collecting rent. 

The rest have a combined worth of about 1.5 million but aren’t owned free and clear yet.All Properties are collecting rent and generate about $16,500 (profit) a month in Cash flow after mortgages/expenses.

Avestor is another company that's offering these combination of investment to be available while they would collect another layer of commission. 

About 4 years ago we purchased a retail center for cash and after stabilizing the tenancies financed $650,000 at 4% fixed 20 years with this lender.  3 months ago this lender allowed us to wrap their note in a new first lien we provided to a buyer with a 10% interest rate - essentially granting us the right to collect the differential between 10% and 4% on the principal balance (currently $610,000).  

During this year, I've experienced inheriting a crooked property manager I let go on day 1 that tried collecting rents from tenants weeks after, an eviction (same person) and a successful lawsuit against a non performing seller that backed out the day of closing. 

If I hired a PM that would also take care of collections (among other things) would I still need a service like rent redi? 

They have 6 figure jobs and just want to collect rental income and move on from their job ASAP.