1. I think i had a cheapo hotel in walking street lined up before I arrived, and then later went to an airbnb.
2. I wouldn't take more than a few hundred in cash, convert it in the airport. Getting money out from ATMs is never a problem you will just need to be aware of fees. If you plan on staying long term and end up getting a job, obviously opening up a local bank account is a good idea.
3. Meatspace always beats cyberspace. Just go to the big park in D1 and sit on a bench and you will literally be approached by young women wanting to "practice their english". I mean this is just one example, the list is endless. Get a teaching job at some retarded language school and fuck the admin staff or your viet coworkers. Apps might be low-effort, but they are also low reward. You're not even getting seen most of the time. I would only bother with apps if you're trying to fuck some girls out in the boonies, which would admittedly be interesting.
5. Waste of time, just go to where the young women are going out to socialize, the big shopping centers, the hugely popular plaza i forget the name of.
6. Its about the same. You can probably find local hotels on average to be cheaper than airbnb.