If the chocolate is red, then red, wine-flavoured chocolate. Otherwise red-wine flavoured chocolate.

Flavoured is unambiguously​ an adjective, so no hyphen needed there.

I don’t think it’s as clear-cut as #1 would suggest. I’ve often seen the variant along the lines of red wine-flavoured chocolate.

This phrase asks a lot from the poor hyphen, but, forced to choose, I'd go with amw (#1).

Agree with #1. If the hyphen is between wine and flavoured, it implies that the color of the chocolate is red.

Assuming that the chocolate is flavored like red wine, the only correct choice is to hyphenate all the parts of the adjective, as English convention indeed requires.

red-wine-flavored chocolate

The question is not whether 'flavored' is an adjective -- that's a red herring. The question is whether, if you replaced 'red wine' with another flavor in one word, you would still need to connect it to 'flavored' with a hyphen, and the answer is unequivocally yes.

coconut-flavored chocolate
peppermint-flavored chocolate
peanut-butter-and-jelly-flavored chocolate

Agree with #5.

I would also write red-wine-flavoured chocolate. Not that the final hyphen is absolutely crucial, but one might as well be systematic.

red-wine-flavo(u)red chocolate... - same here.

red-wine-flavoured chocolate ... wenn's denn Schokolade mit Rotwein(geschmack) ist, wäre das auch meine bevorzugte Schreibweise ...

No hyphens leave it ambigous to me. There are lots of fancy chocolates around these days that are painted in all kinds of colors, so a red wine flavored one could be be a wine flavored one that's colored red or one that's flavored with red wine.