Most of these are common sense. As a tourist foreigner, you also aren't expected to know all the customs but it's appreciated when you try. The one about which direction to NOT point the chopsticks in was new to me. If you just watch what other people are doing, then try to do the same thing, you're probably on the right track.
Related to eating, one pro-tip I got from a local is that when you're ready to close your tab or get your check at a bar or restaurant, you can make a small X with your index fingers.
Really useful in a busy bar!
1. I have seen Japanese people do approximately half of the things on the list.
2. The two listed as "serious" are related to Japanese funerary rites, and so are clearly culturally specific.
3. Several of the things listed are perfectly acceptable in other chopstick-using cultures. Many are also perfectly acceptable to do with a fork and/or knife in cultures that use forks and knives. I think I would go so far as to say that there is not a single thing on there for which it would be widely considered rude to do in all cultures.
> The one about which direction to NOT point the chopsticks in was new to me.
I suspect it mostly affects left handed people.
> Most of these are common sense.
A lot of them are not common sense at all. Even the 'serious' ones require cultural knowledge to understand. Only a subset of the rest would be un-ideal across cultures, which is what I would use to measure 'common sense'.
It's like how in some asian cultures it's rude to bring the bowl closer to you by lifting it off the table, and in others it's the opposite. And of course there's some just-so story for why, that seems to make sense if you don't know about the opposing just-so story.
Things like that aren't what I'd call common sense.