They can use any fruit to make the pancakes. If the fruit gives a moodlet then they will get that same moodlet from eating pancakes made from that fruit. For example, eating flame fruit pancakes will give the flame moodlet for warmth that flame fruit gives, eating plasma fruit pancakes will make a normal sim sick and will fill the thirst of a vampire sim, eating pancakes made with lime, cherries, pomelo, grapes, bananas, etc doesn't give any particular moodlet other than the good/amazing meal moodlet because those fruits don't give a moodlet.