Wouldn't call Sanabria a wonderkid, at least not one of the best. He's quite a talent but I doubt he would have gotten the same hype if he wasn't a la Masia product and hadn't publicly pushed for first team action this much. Even then, he wasn't necessarily better than other attacking talents from la Masia in his age group (cf. Adama, El Haddadi etc), just seems to be more recognised than those because he was one of the very, very few emerging true 9s and a not a wide player. He's done alright in the few minutes he got at Roma so far, but he was never as spectacular at the youth level as the whole transfer saga & Arsenal rumours suggested.
I'd always put Meyer over Goretzka as well. Goretzka, Sanabria etc are very talented but if that's the definition of 'wonderkid' then we'd need to include a hundred players per league/country in the list. There are too many worth mentioning anyway.
From the players mentioned I'd particularly agree about Halilović, Meyer, Sterling though (but those happen to be the ones I've watched the most as well). Ødegaard looks great but the hype about him at the moment is a bit OTT.