It's best to go over each set of drawings while on-site with each contractor. 

You'll be going up against experienced investors, agents/brokers, and other wholesalers who may have their sites set on the same property.

You don't need a site or to pay anyone.

A lot of the sites will push you again to the top when you do a price drop so maybe drop the price like $25 or $50 every week or so until you get it rented.  

The official source I was able to use is the National Association of Realtors site and it shows Multi-family market cap rate of 6.1% for 2024 Q1 (2023 Q4 was 5.7%).

Potential clients do not know of NARPM; and their site is geared towards building membership, not necessarily referring potential clients to it's members. 

Are there any sites where I can check their criminal and evictions if any?

It would be listed on one of the FLW sites, like https://franklloydwrightsites.com. 

After he was successful in being more profitable than his neighbours (one thing he's done well with is driving traffic to his direct booking sites to cut out the host sites that take so much in fees) he started taking on investors that put the 20% down for say a DSCR loan.

Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.