In French 'j' carries /ʒ/ and the digraph 'dj' carries /d͡ʒ/. In English, 'j' carries /d͡ʒ/ and there's no consistent orthographic convention for just /ʒ/ ('si', 'zh', 'j', and 'z' all do the job in different contexts, and probably others as well). There isn't really a /d/ as such in /d͡ʒ/.
Right, but the best explanation for why "Django" is spelled with a <d> is not that the <d> is silent and the <j> represents /d͡ʒ/ but rather that, as you say, the diagraph <dj> represents /d͡ʒ/.
Yes, but when somebody says "the d is silent" they're giving directions to spell and pronounce this word in English, not a lesson in French etymology. Your cure is worse than the disease.
