Send a letter giving them your/pm's contact and a detailed explanation on how to pay the rent (Helpful with older residents if you are going from check to online billing.

I typically use regional banks to fund my deals but my 2 go-to banks have either slowed or fully stopped investment loans so recently I've connected with several online brokers but all came from ads or they reached out to me vs personal recommendations and intros so I have concerns. 

Lots of material online.  

I also did some investigating online and see the renter has a tendency not to hold down a job.I offered asking price (fair market) because it was the sellers bottom line and the fact there were already tenants renting.

I think you are answering your own question here - if you can't find reviews or much info online then....

I agree with the above that Quickbooks Online (QBO) will work for you.

The address was submitted to their red book and now shows up online as official address when I try to ship items from Amazon or similar websites.

Pro: In addition to MLS access your brokerage might provide access to other resources such as detailed online assessment data not available free to the public. 

Online title search companies.

All your first set of questions can be answered by looking online or calling several local competitors.Your accounting questions though, show such a lack of basic knowledge that you probably shouldn't be doing this until you have more experience.