Sorry, dk explanation but as no definitive answer is forthcoming, just some minor tips:
1.best forum for all this, gründlich! is DSO: the german equiv: drehscheibe-online. Most likely as there always, always seems someone wanting to make such trips, there is already some answer with more data.
2.very recently on that forum I read that the SJ Overnite trains for a while=trackworks, would NOt start at Hamburg HBF, but as a minor suburban stop at the end of a S-bahnline; Pinneberg. This may perhaps be the explanation. But somehow I think that was for around Easter. Perhaps a repeat later is planned.
3.you may want to check if some nearby dates -start of the week, or next week, do show trains you want-in such a case it may be that <a>there are trackworks and/or that <b> the final timetable has not/could not yet be shown and you just have to wait till planners in scarce supply have done their job.
In any case-this line on the tunnelbridge via pepper&salt created islands is so important that there will be alternate forms of transport provided if the trains cannot run.
