Yes, I would consider employee theft and data breach to an insured as property claims. These are damages to your things of value. I suppose we can debate whether data is tangible.
In a large enough insurance company, underwriting and claims departments are partitioned into people mostly responsible for property and mostly responsible for liability. If you had a question about employee theft or data breach, I think you would more likely find the company expert in the property department.
The above is again an over-simplification. Some companies are not so partitioned, and some policies such as CMP and Business Owners are multiline and possibly handled by one individual rather than two, especially in underwriting.
Why is this property versus liability distinction important to you?