The previous landlord did offer to just turn the check over to me if it doesn't get sorted before July rent is paid (thank goodness he's been accommodating!)

The seller may not always be able to accommodate but it is an option.

You're being very accommodating.

It'll be tricky to find a deal in SoCal and especially one that can accommodate my mom's needs, but I'm willing to be patient. 

Good property managers (few and far between in my opinion) physically go and check on the guests after arrival to make sure they are happy with their accommodation but more importantly that there are only the number of guests staying that should be.  

The tool will accommodate the processes as you scale your business for growth.

It is likely more difficult to find the seller who will accommodate the seller financing than the attorney to do the paperwork.

It's not an ideal office, but could fit the bill as a temporary solution, plus you could have the basement finished and convert it into a proper 4th bedroom or even a 3rd unit if the layout and zoning accommodates.

Justin, how many people are you hoping to accommodate?

You need to establish a relationship with a Qualified Intermediary ASAP who will act as custodian and accommodator, holding the proceeds on your behalf.