What’s the legal way to collect payments from roommates that live with me in the same house? 

The LLC collects rent, pays expenses, and distributes funds to the owners based on your partnership agreement.

It's completely legal that's what I do I pay the bills to the utility company and send a copy to the tenants and collect the 60/40 split from them each month

They now collect that informaton at the birthing hospital. 

I'd also suspect that as an owner-occupant, one might be able to skirt strict STR laws, and rent out a primary in an extremely in-demand market, especially in the near-term (think collecting huge fees seasonally around CU football games the next few years). 

Avail, Apartments.com, Buildium, RentRedi, and several other platforms allow you to make leases that can be signed online electronically and also will then collect rent through their portal. 

The owner's title policy premium, title search and closing services (collectively, "Owner's Policy and Charges") shall be paid, as set forth below.

Kinda nice because now you get to be the bank and collect payment on your terms, instead of the OTAs using the guest's for their own liquidity need until they pay you out. 

I collect the first month's rent the day they move in.In my area, I am comfortable working with the existing tenant to arrange showings before they move out.

Appreciate the BP community collective!