Multi-language/default language naming conventions

So, speaking of New Brunswick, I noticed that many streets in the Moncton–Dieppe area are still missing the French name. As I went along chemin Shediac Road adding what I could from street-level imagery, I followed the format “boulevard … Boulevard”, which seemed to be the most common format in that neighborhood, though “Boulevard … / … Boulevard” was also common in other neighborhoods.

I did run into some streets that illustrate the pitfalls of literally tagging what’s on hybrid signs. Apparently the signs for Marche Street say “rue du Marché st”. Should there be no name=* just because “Rue du Marché” and “Marche Street” share no words in common? Or should both names appear in full, as in Place Champlain / Champlain Place Mall? (And better yet, with a semicolon?)

Also, should name=* and name:fr=* begin with a capital or lowercase letter? Unlike in Winnipeg, many signs here capitalize the French road type, and I believe this form is appropriate for map labels and address labels. However, lowercase would be more correct in a sentence, such as in turn-by-turn navigation instructions. In either language, one can easily capitalize a lowercase string as needed, but it’s harder to reliably go in the other direction. (This isn’t true of every language.)