Hard to tell from that video sorry but what I could glance was the first DB coaches looked liked ex DR rebuilds and the one with the windows grouped in two looked like an old couchette style car (once made by roco).
I'm not sure anyone does the PKP sleepers as a model. (IIRC the one with the writing on is very posh with en suites and DVD's.)
Heris might be your best bet:
http://www.heris-modelleisenbahn.de
As for the Russian coach the only one I've ever seen made in that colour was an old sachenmodel one (came in a set of 4) which I have. But it was the modern one, which is shown and was made in Germany
http://www.bahn.de/nachtzugreise/view/reiseinformationen/reiseinfo.shtml
might have some more info. (beware, lots of ads)
If you know the train number this might help (346 looks like the one you want)
http://www.fernbahn.de/ and then click on:
Wagenreihungen der Deutschen Bahn
Hope something here helps.
SJ