We offer a $200 referral fee, and have been considering increasing it. 

The first few times, I didn't charge a late fee.

Subtract the flat fee buyer agency fee of $6000, meaning the buyer is credited $6,500 at closing.

Some, like ours, focus on offering optional services such as renters insurance or washer/dryer rentals without requiring tenants to opt into a full package.When choosing a property manager, I recommend asking about the structure and purpose of any fees.

What are options for having our investors pay their share of this monthly fee?   

Quote from @James Hampton: How about a quick check before you have to charge a screening fee? 

Total loan is $500k so the other $400k comes from other investors.My husband invested in a note with Aloha last year as a trial, and unfortunately that one went into default a few months later.

Beyond that, sending upfront fees to a lender is not okay.

Most folks are charging 10% of the rental rate for monthly PM fees. 1 months rent for a leasing fee and couple hundred for a lease renewal.

Quote from @Jonathan Bombaci: This year, our management company, which oversees 700+ units in Massachusetts and New Hampshire, spent over $209,000 on attorney fees, primarily related to evictions.