Thank you @Helen3 !
The property management company said they were fine with any arrangement and cohost was perfectly acceptable. They also preferred to keep the listing - they were not trying to encourage me to start over.
The company just said they had not taken a listing over before so would come to me with a recommendation on how to integrate the channel manager into my existing listing if possible but they were fine being cohost on Airbnb and integrating with the other channels since I only have VRBO established and only a couple of reviews there.
I have discussed with references, and all seems solid.
They charge 30% of the booked nightly rate to fully manage all aspects. That 30% includes all STR fees, cleaning costs, guest use products (higher-end paper products, soaps, trash bags, detergents, coffee filters, etc.) and all maintenance labor. Over my three years of managing the property the cleaning costs alone were more than 30% of my nightly rate 2 of the 3 years I have managed the property. I pay more for each cleaning than I pass on to my guest. This is a longer story and an agreement I am happy with since my cleaning company is the best and extremely reliable (I manage from out of state) but I don't feel justified in passing that whole cost on to my guest. I manage this through encouraging longer stays so I incur the difference in cost less often and it is working out well. All that to say, once I include maintenance labor, guest-used products and fees, the numbers make sense for me. Plus, I do project more revenue as a result of more channels.
Thank you again and this makes me think that maybe asking them to be cohost on Airbnb and then use their channel manager on all non-Airbnb platforms in the name of their property management company since I don't have much built up there as of yet.
Thanks again for all thoughts!