Speculation time XD...
Had Aizen influenced creation of Fullbringers in some way? We know Aizen experimented with hollowfication---->creation of Visoreds. Is there any possibility that his experiments resulted creation or rather birth of these unique individuals.
"Fullbringers each have a parent who was attacked by a Hollow before they were born." (wikia).
Maybe Aizen arranged the hollow attacks. May be the earlier experiments were failuers and he abandoned his experimentation, unknown that some individuals were born with this kind of powers.
All these great writers like Kubo, Kishi, Oda, etc. are able to link the events of the past to the recent. I will not be surprised, yet again, seeing Aizen's involvement in the story. Even if its only the reference.