Key to open the dark

I'm a major kh fan and ive never seen the secret endin so i need questions anserd 1.how the heck are the "lost two" i heard of and what happened in the keyblade wars i mean in the first game leon made it sound as if Sora could be the only keyblade weilder. and y do i have the suspicion Xahnort never actually died. and lastly when will it be released because i WANT IT NOW!!!!