Origami Pig (Riccardo Foschi) 

You are totally right, but 2 colored paper that I know is very thin, some models need thicker paper such as tant paper or canson paper which only exists in one color to my knowledge

Good question, I think so, I never tied but it should result as a single color even if using a bicolored paper, in the end

I actually have one very simple cat, check on my youtube channel

Ok! I will check it out

I would love to know what wings tutorial you used, please, as I also want to make one with wings for a friend

Ma certo, che domande é un piacere! ed in ogni caso in generale sei libero di condividere la tua arte come meglio credi! Il permesso ti serve solo se vuoi vendere un pezzo o condividere un tutorial, ma se si tratta solo del modello finito puoi condividerlo senza nulla osta del designer originale :)! Grazie per aver chiesto in ogni caso!

I've used Tant paper