Alright, here are the RainbowPie kids:
 
Name: Pinata  
Age: Stallion  
Role: Owner of a party supply’s store, elder brother  
Talent: Creating the best party supplies around!  
Personality: He is more or less grounded than his little sister, taking after his mom, Rainbow Dash, a bit more. However, he loves having a good time, playing with his sister, and flying around Ponyville and helping whoever needs to be helped. He is always in a good mood, so if he were an Element of, lets say, other elements of Harmony, he would be Optimism!
 
Name: Streamers  
Age: Filly  
Role: Party-thrower, youngest daughter/sister  
Talent: Throwing the best parties ever!  
Personality: With her attitude bursting with confidence and energic joy, this little filly is quick to make friends and always keeps her promises, or at least, attempts to. She can be very stubborn at times, but can be introduced to new ideas indefinitely. She wouldn’t be apart of any elements, but she would be a key factor for Pinata’s reason to be an element.
 
bases by Softybases (i think)