Tbh no offense but this sounds like copium. We don't know what status babies fathered by CDs and slave women have in Marigeoise. They might inherit their mother's slave status.
saturn experimenting on celestial child even though half blood. i doubt.
saturn has stated bonney is kuma child he never said your foster father etc, even threaten kuma he make bonney a slave. because of kuma blood.
imo that looks like saturn was aware/spying on kuma and ginny. ginny prob trying to trap kuma in marriage after she finally realized she was pregnant why she wanted to meet up with kuma in excitement.
like even when kuma said he give his life away to cure bonney, saturn had a spy den den mushi waiting and ready. imo that point to a traitor. and usually the traitor tells kuma where to go to vega punk, so saturn can watch his plan unfold. or that den den mushi never would been there.
saturn planned it, and had a traitor from kuma side.