We will at one point want to produce paper output, so I think it's a good idea to start coding these in now.
No, please make a different project for this. I already hate the interlanguage links, we don't need more of this meta stuff in the article source text.
I don't want to know how many people hit on "Edit", see the interlanguage links ([[ru:%D0%9C%D0%B0%D0%BC%D0%BE%D0%BD%D1%82]] ...) and think that it's too complicated to edit articles.
What about the idea to keep these in a separate database (and not in the article)? I think this was discussed before, but nobody seems to be motivated enough to code it.
Kurt