кого-либо is the genitive case of кто-либо.
кто-нибудь = кто-либо = anybody, no information is known about the body
кто-то = somebody, some information is known about the body

Например:
кто-то пришёл. = Somebody came. A physical person walked through the door.
кто-нибудь придёт? = Will anybody come? There is no information about who will come.

Same thing with куда
куда-нибудь = куда-либо = anywhere
куда-то = somewhere

I don't know the difference between кто-нибудь and кто-либо.