Interesting thread as i have been asking myself the same questions...for different makes and models.
I have an image in a book of your first square vase with a moulded signature 'SPIP Tchecoslovaquie'. Sofar i've found out that it used to be a parisian importer/wholeseller, who used to have their own vases made overthere. It is interesting to see it under a different mark.
The Luxval 'Maïs' is a new one to me, not the model of course but to see it under a different brand name. As far as i have been told, all the moulds were destroyed at some point, at the end of the Luxval production. I haven't come across a known Luxval model under a different name, except for 'made in Belgium'
I guess that certain, more popular models in general were sold/leased or perhaps commissioned. A good example is the wellknown 'Cornet' vase with tulips as decoration, that can be found as Inwald, Barolac, Markhbeinn and even signed 'Belge' and 'Fait en Belgique', and it is especially the last two marks that puzzle me.
I have come across the Atlas series also under the belgian marks, as some other Walther and Hermanova models, but i can't identify or find an importer.
The well known 'Luxor' vase is found in several catalogues, and once again, with both belgian marks on it.
'Fait en Belgique' and 'Belge' is often attributed to Manage and Scailmont but recently i was told about a tiny factory called 'Fauguez', situated in Belgium, but long gone now.
All of this makes me believe that factories used to either work together, trade or copy. The wholesellers seemed to have jumped on the bandwagon by distributing the same models under their own brand, which makes things even more complicated, because i then ask myself, who did the original model belong to? Perhaps with Argentina this is the case as well. A lot of europeans moved to south america during and after the war, so i can imagine, a lot of people in the glass trade did so too, so maybe there's a link there. The ''Moser' story for example, is proof of that, when they moved to the States in 1940-1941 to flee the german regime. In Argentina the factory Cristalerias Papini used the full words INDUSTRIA ARGENTINA moulded on several of their Carnival Glass patterns.
I guess that copyright/patent was less strong in those days, and therefor popular items were easily reproduced, but this is all food for thought, well..for me it is.
Any thoughts from anybody?