I love it! Samson is such a cool name, and Sonny is a cute nickname. Although, personally I think it would seem like you were honouring your sister. Samantha and Samson are very similar when they exist in the same family.
agree...And if my name was Samantha, I would think my sister had me in mind naming her son Samson, and if we didn't get along, I would still tell friends she named him in honor of me, just to cause aggravation for her.