Hayden Romero:
Hayden always calls you Babe with a smile on her face, which only happens in happy moments. In serious situations, she either calls you a nickname related to your name or just calls you by your name.
Tracy Stewart:
Tracy calls you Babe, just like Hayden, but it took her a long time to get the courage to call you that, at least in front of Theo. When she called you that in front of him for the first time, she had accidentally let it slip out but Theo just looked at her with raised brows.
Malia Tate/Hale:
Malia calls you multiple nick/pet names, one never stuck with you for more than a day. Actually even when you get mad or upset with her, the way she always tries to break the silent treatment, is by calling you all the nick/pet names she could think of in a row, waiting just about a seconds between them only to see your recation at her annoying you.
Kira Yukimura:
Kira just stuck to calling you by your name or your actual nick name sense she gets really awkward just by thinking on calling you a 'pet name', so she kept it simple.