Welcome to Librarium Online!
I have started a Slaanesh daemon army and have build three pleasure seekers, now the question I have is can I use then in a mortal Slaanesh army as a special choice? What about Daemonettes with the command upgrade? Or Slaanesh daemonette chariots?
Short and sad answer to all: NO :cry:
Well, as far as the models go, you might prox them as a mortal slaanesh chariot and slaaneshi chaos spawns (I personally wouldn't mind the probably different base size)
and the daemonette command group would have to go as regular unit models.
It ain't easy bein' green... :-)