Is it reasonable for Qingdao Freeport B&B to charge property fees?

Unreasonable. There is no difference between staying in a homestay and staying in a hotel. The room rate you paid has included everything. Water, electricity, heating, property fees and broadband fees have been included in the total room rate. Operators have no reason to ask consumers for this fee. If there is a property fee for staying in a homestay, then obviously this fee is unreasonable.