Maybe it depends on where you apply. I applied in Tokyo and they just needed to see a certificate of my bank balance at the time, it didn't need to show 3 months before or anything like that. If you apply somewhere with the same rules at Tokyo, then perhaps you can ask your parents to put the money in your bank, get a certificate of bank balance and then pay the money back to your parents right after that. Good luck 👍
Pretty much any landlord would bite your hand off. If you find something you really like and you have enough cash, perhaps think about paying a lot up front (6-12 months) so that you can negotiate a better deal. Plus you might be able to get a bank account if you find an agent with a very good relationship with a branch manager of a certain bank. Good luck
No it's not normal, but I hear that it's a somewhat common alternative to be given a tourist visit if for some reason you didn't qualify for the DTV. You could question it with them, but I doubt it's a mistake