⊱.S.
Hello,
What is your understanding of being a godparent? Are you considering this as your choice should you and your husband die while your children are minors? Or are you thinking of this strictly in terms of your faith? Because being a godparent is not a legal and binding proclamation of who your children would be raised by should your children lose you. That should be put in a will or a trust.
I'm asking because if you are really intending to choose who would raise your child, there are so many factors to be considered. However, if this is per your religion, say Catholic, then that may be something altogether different and I would choose someone who is strong in their faith and whose relgious beliefs align closely with yours. In your eyes, what IS the responsibility of a godparent?? Only you can answer that and choose the right fit. Not your sister, as well-meaning as she may be.