1. Always good to print a copy of flight itinerary, or at least keep a print screen or email ready for inspection. Some airports might require you to produce some form of proof that you're flying before you even get to enter the airport for check in. Some airline check in staff and immigration officer might ask for your return ticket.
2. If you plan to take a cab, good to have the destination's name and address in their native language.
Point 1:
Sometimes just show the passport can already ...
then tell them your flight
Point 2:
Agree with you. If you are staying those not so popular hotel, or smaller hotel, sometimes the driver might not know where it is ...
Print the hotel name in that language, plus screen shot the road names in that language , to show the cab driver ...
Dirty also is my own germs, nothing to worry. But most of the time I will get my clothes washed before leaving a place. 
