Genetically? No... But Cream and Sonic appear in the same games like sonic heroes and sonic advance, but they are not cousins or anything.
Cream the Rabbit
No. Cream is 9 and Sonic is 23. That's as crazy as Taileam or Shadamy.
Cream the Rabbit's father is Vanilla the Rabbit. Cream and Vanilla are often seen together in the Sonic the Hedgehog series.
Her friends are Sonic the hedgehog (brother), Silver the Hedgehog (brother), Shadow the Hedgehog (brother) and Cream the Rabbit (close as sisters).
Sonic the hedgehog,
No, Cosmo's mother is shown in Sonic X. Sonic the Hedgehog's mother appears in Sonic Underground.
There are a lot of good guys in the Sonic series, so I'll only list the main ones: Sonic the Hedgehog, Miles "Tails" Prower, Knuckles the Echidna, Amy Rose, Cream the Rabbit, Silver the Hedgehog, and Blaze the Cat.
No, he was always a hedgehog and always will be.
The name of Cream's sister is Vanilla the Rabbit. She is a character from the Sonic the Hedgehog franchise, introduced in the game "Sonic Advance 2." Vanilla is depicted as a caring mother to Cream and is known for her gentle and nurturing personality.
Cream the rabbit out of Sonic can fly with her ears.
Rabbit
Sonic just likes cream as a friend, so no.