L.M.
Picking "Godparents" depends on your definition/intention of their role. A true Godparent is intended to help bring the child up in their family's religious beliefs. Many people pick godparents with the intent that if something were to happen to the parents, the godparents would become the child's guardian (which by the way does not happen automatically, you need a that to be spelled out in a will or other legal papers). Some intend on both. What is your definition/intention? You should decide based on your answer.
There is nothing wrong with picking the same or different Godparents for each child; however, if your intent is for the Godparents to be their guardian if something were to happen to you, then you would want them to be the same so the children would be together if that were to happen.
You should not decide based on how someone will or won't react. You have to do what is right for your family.