Anything with needle type bearings shouldn't get moly (Ujoint spiders have needle type bearings) I also wouldn't use it in roller type bearings (wheel bearings). Slip joint/slip yoke could take moly- but in my experience, the heat created in that joint dries out moly type grease fairly quickly...
My 05 FSM has the slip joints facing the diff's- however I run the opposite- slip joints towards Tcase.
Im not sure it makes any difference which direction their mounted.