I don't think you can have too many.
DD has two but DS ended up with four (two godmothers and two godfathers). One 'set' of godparents is the same for both DD and DS and they will also have guardianship if anything ever happens to myself and DH.
DS ended up with my BIL/SIL as well as DH is very close to his brother and wanted him as godfather to our son.