We Are Your Perrents Noooooooooooo

is cadens and sunset shimmer sisters?

well they do possess the same color macik and we see that when sunset get evil she gets her father's powers (sombra) see other headcanon)
and we haven't seen cadens evil jet
but ok imagen starswirl coming to the crystal inspire coss he hears that his friend the king is sick and cant take care of his subjects (under the love poison) starswirl go off and comes to the cassel (he has the necronomicon book with him)
to keep them apart for 1 huver he cast the spell from the book on to the king.... and he becomes sombra fully the queen still under the influence of the position becomes crysalys in time after starswirl or she cant say to the king how they fell coss they both love him to muth? the king gets angry at the queen and try to kill Cadens and sunset simmer starswirl see this and try fight sombra off..... but cant he now point his rage on the qean and turn her into crysalys in front of caidens eyes. caidens trying to save her mother jumps in the fire and gets her cutie mark and also the crystal heart is made out of  crysalys old heart.... brrr.....
after becoming qusalys she disappears into the night and starsirld gets a message to celestia and luna for help and they come bannish sombra... to late to save starswirl but celestia makes cadens a alicorn and see the other small fold names her sunset shimmer and take her under her wings... as with cadens but she already knows what she is supposed to do so she becomes twilight fold sitter and fall in love with shining armor (also still believe twilight learn the wanted need it spell from cadens)
after banishing sunset simmer Celestia ofc don't know they are sisters to Candens coss king sombra wipe the memories of them and disappeared with the empire so sunset then go to the portal and you know the rest... so sonset looks like her father and cadens as her mother before she becomes crysalys... therefor they are in familie or sisters this will be a handful for twilight and celestia and luna... ohhh luna how she will begin to understand sunset and cadens more after this...