You can only fins these at night. if you see the bellboy sim at night he will appear in certain spot (i least i think).
choose the option: join rocket launch. when there done building they should launch it. the rocket will fall. obviously nows the time to grab it. now for the ghost essence: at night you can find a ghost that appears anywhere in town (randomly) choose to be nice (i dont know what being mean does). sometimes the ghost will scare your sim (gives you scared essesnce) but if you hug: the ghost will drop the ghost essence. the ghost will dissapear if its morning or at random. i hope this cheat is found useful.