So here’s the first of the family portraits! This is Twilight’s family!
 
From left to right we have  
Tempest Shadow  
Sinbad  
Shadow Flicker  
North Star  
Dark Kiss  
Twilight Sparkle
 
Mythic Show  
Party Favor
 
I don’t want to reveal too much since the story will be revealed during Mythic Show’s arc, but Mythic Show is not allowed to be part of Twilight’s life. He is aware of his relation to her and her family, but is not allowed to interact with them. Mythic wants nothing more than to be acknowledged by his mother.  
Tempest is aware of what happened between Twilight and Party Favor, she was mad at first, but has long since forgiven Twilight for what happened.  
The rest of Twilight’s children are completely unaware of Mythic Show’s existence