Two NOT CHANCEsUpdate from Sue, concerning the plate with the yellow & red Oriental pattern: she has seen one with a Filigranglas label, so definitely made by Unionglas in Germany!
Anne B: regarding your mermaid dish, this may have originated from Denmark. The reason is because the decorating of slumped glassware was independantly developed by a Danish company in the early 1950s, so this might make sense considering the subject matter!