Does ריבה mean both jam (that you spread on toast) and jelly (the wobbly pudding)?
If in jelly you mean fruit preserves then yes. in Hebrew we call gelatin dessert ג'לי (je-lly)
It sounds very weird/unnatural/wrong in English. If someone asked the question that way, I would assume that they did not know English very well.
You could potentially say "Dogs eat jelly?" with the right intonation and be understood, but "Eat dogs jelly?" just sounds like a nonsense phrase.
the grammer (EN). it is as if you've asked if someone ets "jelly-dogs", while the sentence in this practis is "do dogs eat jam?". BTW, jell-o in hebrew is ג'לי (sounds just like jelly), while ריבה is jem and קונפיטורה is confit (though in every day usage people useally mean jem when they say קונפיטורה)