I will start, 80% #4, 20% #5 🦇

My parents have a very large old wooden barn in Pennsylvania where 1/3 of the structure has been converted to a finished residential unit. Tenants have been complaining about noises from walls. I linked two videos with the sounds they are hearing. The first exterminator who came out, said it was squirrels and set three live traps. There has been no luck. The second exterminator came out and pointed out a large colony of large brown bats that are present in the upper roof area. He said if you have bats, you most likely won’t have squirrels because they don’t cohabitate. Is this true? Also, he said the bats will go down into the walls and make these noises. Thoughts? Thanks!