...then VicDan's child would have only four godparents. But that is not any long-standing tradition. King Carl XVI Gustaf had ten!
That being said, if there were only four, it would most likely be the following:
1. CP Haakon (other Scandinavian heir)
2. CP Frederik (other Scandinavian heir)
3. Prince Carl Philip or Princess Madeleine (paternal uncle or aunt)
4. Anna Westling (maternal aunt)
This seems closest to the selections used for the godparents of CP Victoria and her siblings.
If they select more than four, the list could include any other combination of VicDan's siblings, cousins, close friends, other reigning monarchs or heirs/spouses (most likely Willem-Alexander), etc. I would hope that if there are any other royals in addition to the two already mentioned that it would include potential godmothers who have demonstrated that they are similar in temperament/mothering style to what I believe Victoria will be (Maxima, Mette-Marit) or who seems to be a calm, professional, good example (Mathilde); or for potential godfathers ones who seem professional and relatively scandal-free (Philippe, Felipe, Guillaume - even though they are all Catholics).