First week in the condo my fiancé says the bathroom drawer was wide open all the way, when she 100% knows everything was shut when leaving.
That same week, she notices the same thing but with the kitchen drawer for forks, spoons, etc.

... see the desk filing cabinet door open by itself.

I know it's not the question, but before jumping to ghosts and spirits, have you checked that the drawers are level? I have a single drawer in my place that is ever so slightly not level. If there is too much stuff at the front of it, it will slowly roll open. Get a level, and see if the thing is flat.

Other note, if you suspected that you were buying a property from an estate sale of an elderly individual, the chances are fairly high that the previous owner died in the property. This really should not be surprising.