Thank you, guys!

Also a short update from QR office in Osaka. According to an agent (who checked with headquarters), Rail and Fly option is only available if you do not start your trip in Germany. So, having FRA-DOH-ABC flight does not entitle you for Rail and Fly option (which I found a bit strange). Flying ABC-DOH-FRA, however, does.

At the end, I went for nonstop with LH: 20 eur more than QR, but less flying and higher chances for an upgrade...