D: I dunno if this tip helps but for eyes I've found it best to just putty in the eyes and then use the stem to move them where you want them and give it a good pat down.
If your using hot glue...I find that layers of skin need to be sacrificed to the hot glue god in order to keep them in place long enough for the glue to dry.

As for wigs, I found these uber flat velcro squares that are keeping some of my wigs in place. Alas, however Ashtan's Elfdoll wig seeks not to cooperate and might have to either be put down or have more velcro installed.