There are factors that allow us to increase carrying capacity such as artificial feed and aeration. These 'non-natural' factors let us push certain envelopes.
In your case, I would think your bluegill are going to spawn this Spring '23, and your pond should be polluted with fathead minnows if they were stocked in the Spring or Summer of '22.
If you stocked the bluegill and fatheads in the Fall of '22, I would wait until the Fall of '23 to stock predator fish, and I may not feel the need to stock any additional bluegill or fatheads depending on what you're observing.
Also, why haven't you started feeding? Those 4-6" bluegill could have been on feed from the day of their stocking.
