The plural of Château is normally formed by the addition of an “x”, Châteaux, hence the form “Châteaux La Violette and Le Gay“, short for “Château La Violette and Château Le Gay” – pretty much like saying “Presidents Macron and Putin”.
Why didn’t we use this form also in the Portuguese version?
Maybe because we feel that English natives, precisely because their language is distant from French, are more likely to use their formal grammar memory when reading in this language, the same being applicable to non Latins browsing in English – the fact that a large portion of these no doubt learned English at regular school would be a possible indication that they will also be acquainted at least with the amount of French that English natives generally are.
Latins on the other hand are much more familiar with French from the start, as natives of closer languages, but this knowledge is in-built in their own – Italian, Spanish, Portuguese, Catalan and so on. It’s a much deeper knowledge than one due to grammar study, but it lacks detail and contact with the written version of the language.
French is also less present today in regular schools in Latin countries, especially in Latinamerica, than in the anglo-saxon world (and possibly in Asian countries).
Hence perhaps the paradoxical impression that in general the feeling of Latins who don’t speak French is in such case inferior to that of other internauts and that they would tend to misunderstand that short form.
Marco Juliano e Silva