Unfortunately, this is not yet known. However, as soon as a recording is possible, we will immediately make an effort and put the article online.

Not locked. You have to connect the Kindle to your Amazon account and only then can you download any book you purchase thru your account.

This reader does not have a blue light filter, currently only the Tolino Vision 4HD or tablets with LCD (not E-Ink) have one.

Normally not. Unless it is a so-called Kindle MatchBook. But even then, the Kindle variant is only offered at a discount and not for free as far as I know. http://www.heise.de/newsticker/meldung/Amazons-Kindle-Matchbook-E-Book-Rabatt-bei-Printkauf-1948273.html

No, the Kindle does not have a headphone jack.

Yes. The version with advertising is marked "Special Offers".

Bistahltoni With the NZZ it works fine, it costs nothing but a (free) registration to download the texts. Good luck! Heinz