I think Sora will learn fusion with Cloud because he look likes a mix with Vincent and since they are both confirmed for kh2, it would look kinda wierd if that wasnt a fusion. Since you use two blades while in fusion, BHK doesnt seem like the person to teach Sora...I hope they have Square Characters get move involved and from seeing that Auron saves u from the beast, maybe my hope will come true...BHK just seems like he doesnt have to fuse to wield the power of his blades...so no he wont teach him