SO. A few changes to Roseverse couples.
 
I decided I like Rumble’s personality with AB more than Featherweight.  
Applebloom wasn’t a fan of Rumble in the beginning.
 
Rumble was sarcastic and hotheaded when they first interacted. He liked to play stupid games and manipulate situations and turn ponies against each other. In his early 20’s Rumble got his gf Toola Roola pregnant. The two had an on and off again relationship filled with tons of bickering and verbal sparring. They were in one of their off-patches when Toola gave birth to their son Solstice Sunshine. Unfortunately, Toola passed away due to complications after his birth.  
While the two had a difficult relationship, Rumble was devastated. He felt horrible for not being present when she gave birth.  
He lived alone in the centre of Ponyville with his newborn son, grieving the death of his ex-girlfriend and what his life could have been.
 
Rumble turned his life around after that and stepped up as a father. He had no choice. This foal needed his only parent.  
He became very involved in Ponyville event planning and even got accepted into the Wonderbolts.
 
Through his activities in the town, he became reacquainted with Applebloom as he sent Sunny to a daycare AB and the Cruisaders ran. Sparks flew as AB was taken by the huge 180 degree improvement Rumble had made. And Rumble was smitten with the strength and vitality of this hardworking mare!  
The two would eventually marry and Applebloom adopted little Sunny.
 
They went on to have two more kids Tiny Seedling and Brina Cupcake.  

 
TL;DR Sunny’s new full name is Solstice Sunshine and his birth mother is Toola Roola but he was adopted by Applebloom!