So I'm pretty far into the game now - invading Skull Island- and have collected a bunch of odd items along the way. Anyone figure out what the use of : Voodoo Dools, and an 'aladin' style lamp do?

Ah! It seems to be class dependant. The 'invoke' option doesn't appear for all my characters, but when moving to other's inventory it does.

Gold lamp has been explained. :) You can also make a dummy character to summon him again for an old character if need be. (Multiple plays or focusing on one powerful PC.)

Voodoo Dolls are pretty much worthless. They cast a curse, which can be invoked on a party member or enemy. It very often fails on enemies, however, and doesn't seem really worthwhile to use a turn on. Sale fodder, as far as I've used them.