Hello Juliux,
Your first chap, Werner Feldhoff, was born in Dbg. (=Duisburg)-Hamborn in 1926. His promotion levels in the DJ were Hordenführer, Oberhordenführer, Jungenschaftsführer (1940), Oberjungenschaftsführer and then Jungzugführer (9 November 1942 - typically promotions often took place on Hitler's birthday or, as in this case, on the anniversary of the Beer Hall Putsch).
On the reverse side are the assigments, i.e. the actual levels (Dienststellung/official position). From Jungzugführer, Hauptjungzugführer, Fähnleinführer, Jungstammführer to Stammführer (the last two are missing the stamp). Quite an impressive career, I would say.
The second is Karl-Heinz Schubert from Hamburg, Bann 76 Otto Blöcker, which you have surely seen yourself. He was first a Hordenführer in the DJ, then reassigned to HJ-Rottenführer, then Oberrottenführer.
He was appointed Jungzugführer and in 1943 was a KLV-Lagerunterführer (=sub-leader in a camp), in Babylon, a few kilometres away from Furth im Wald, in the Oberpfalz/Bavaria.
Number three, Walter Warnke, comes from Hamburg-Fuhlsbüttel. It says on the back that he was appointed Hordenführer on 9 November 1941 and was already put in charge of the Jungenschaft 3/2 on 1 October. Signed by the Fähnleinführer 26 of Bann 186, Rolf Rettberg, with the rank Jungzugführer (funny stamp: Jungenzug).
On 20.04.1942 Warnke was promoted to Oberhordenführer. Signature of the k.-Fähnleinführer Rudolf Schmidt, Oberjungzugführer.