I just made this for the girls, the system is the same once you found the right objects. You can do it another way, but this one cost less money.
cook/ginger nurse (like food): truffle(2xlvl1,3xlvl2, 3xlvl3)
cupcake(1xlvl3, 2xlvl4)
Divya (likes shiny rocks): amethyst (2xlvl1, 3xlvl2, 3xlvl3)
emerald (1xlvl3, 2xlvl4)
brunette dancer: black candle
skull ring
blonde dancer (likes cute things): teddy
white candle
brunette nurse: red wine (10$)
martini (100$)
As for the flirt, you need to progress with the story I think.