I don’t recall the Captain Sailorbird intros, but I do recall the foreign cartoons badly dubbed into English, and I remember Johnny the Giant-Killer (AKA Johnny Little and the Giant, AKA Jeannot l’Intrepide) from the description. I’ve been trying to recall which cartoons these were that I saw so long ago (on Claude Kirschner’s kid’s TV show out of NYC, IIRC). This certainly seems to be it. A real Blast from the Past.