Drinking outside isn't illegal in Japan. It commonly happens in spring for cherry blossom viewing. But the cops could be called if they got too noisy, I guess.
Why couldn't you do both at the same time? Sounds very arbitrary.
Not to mention "being able to take care of themselves" isn't very precise. I imagine you think that means living by yourself and paying your own bills and such, but then at that point are you expected to never ask anyone for help...
I can't figure out which games he is talking about on the last page, are the names correct? He mentions "zabura zas", "tantorol", "koramus 3" and "spirit*white magic writing magic battle of the strongest".