The Dutch printing (actually a German text printed in the Netherlands) was a purely commercial enterprise between Thomas Mann and his Stockholm publisher Gottfried Bermann Fischer. BF wanted to publish it in Stockholm, but he was afraid of acting against Swedish neutrality, so he managed to get it printed in the Netherlands under the imprint of Secker & Warburg. The publishing house BFV was part of a consortium of three publishers (Querido, BFV and Allert de Lange) all printing in the Netherlands, binding in Hungary, etc. where prices were lowest and/or printers most experienced in German typesetting. "Dieser Krieg" was printed in March/April by Thieme in Nijmegen and delivered by "Zentralauslieferung" Amsterdam. There are letters about this between TM and BF. The first copies were ready for sale before 19th of April 1940 (I have found archival material about this). A handful of copies were sent as presentation copies, but before sale began, the Wehrmacht entered the Netherlands on 10th of May 1940 and the Nazis destroyed the rest of the booklets en bloc. Actually I have direct access to one surviving copy and know about its provenience. The only thing I am unable to establish is how many copies were printed. The TM bibliographers Bürgin and Potempa postulate a number of 1000, but I am unable to verify this.
There are three introductions to the text: a) the Nijmegen-printed one (in German) (S&W for BF), b) the London one (S&W, English, but identical to the leaflet, even if the leaflet contains one sentence lacking in the English edition and underlined with red pencil in the typescript) c) The American one (Knopf) presenting a new introduction and several sentences lacking in S&W. Nearly all of these additional sentences are not, as one could think, corrections or later additions by TM, but fluid parts of the original manuscript. I don't understand the exact sense of these omissions/additions.
Thomas Mann wrote the new "introductions" (actually the beginning sentences of the text) himself, the last one, the Knopf one, on 16th of April 1940, as explicitly mentioned in his diaries. War evolved and TM had to be up to date. On the other hand there is no trace left in the manuscript or in the typescript of the first introduction as printed in the Netherlands.
Concerning the propaganda activities of Rickman et al. , I have read a very interesting 140-page-file from Riksarkivet, Stockholm. It contains detailed police interviews with all those involved in the Rickman-propaganda, showing in extenso how the propaganda cell worked, moreover containing descriptions of several Rickman-leaflets as far as known to Swedish Säpo. Moreover Tommy Jonasson - whom you certainly know - was so kind to give me a copy of a chapter he wrote years ago on the Rickman propaganda and he added a photo of a propaganda leaflet he found in Riksarkivet, apparently printed by Ture Nerman for Rickman.