Astra has a genuine fear of winding up alone after the death of her father Luno. She wants a family and really wants her mother's affection more than anything in the world.
Psychoborg has an aversion to medicine because he underwent becoming a cyborg since the day he was born which is a process people usually undergo when they're 18 and up. Part of the process means taking chemical baths and even drinking a lot of chemical cocktails for years. It's rough enough for an adult, but for a kid, it is traumatizing so imagine having to take medicine for the first five years of your life. Due to this, Psychoborg despises medicine especially in liquid form.
Prometheus (the Monster) has a fear of water because he is a clumsy swimmer and when he first woke up, he was submerged in it which traumatized him. He is also afraid of what his true identity is since he is an amnesiac.
Igor does take well to the sound of a whip because his grandpa who used to live with his family would abuse him physically because he was ashamed of him (he's a hunchback). Luckily, his realized what his grandpa would do when no one was looking and threw him out of the house, but not before the trauma set in. Now, when Igor hears the sound of a whip, it causes him great distress and if it goes on for too long, he will get an anxiety attack.