Hey pal,
Sorry, I forgot about this. I tried the Croissant model as well as Tower Instruct Mistral, and after some tinkering.. I believe that there isn't any EN-FR LLM out there today that realistically can work in a game format. They'll hallucinate and break often when translating singular words or questions. They seem to work fine for any paragraph type of translations, which is great, but it falls completely flat if you want to use it for anything more than that.
If your main use case is to translate longer sentences or paragraphs and can't get it to work, let me know.
As for the one-shot-fits-all solution, it is a work in progress.. haha. I find it hard to know exactly what to put there and what not to.