Polish aplication from Slovakia

I'm working in Slovakia (besides A1 form in Polish language I don't need any other work permit) and the best date for me to apply for visa are the opening hours in Wien. Can I apply for visa in Wien even if I have no bussiness there to work or be there, besides the visa aplication? (what should I write in the form in point 1.25). The home address (1.18 till 1.21 can I fill in with Polish address?). 2.6 the itinerary is not specified yet, we know we would like to stay in Beijing, but is the hostel reservation necesary? Kind regards