Normally, Homies created by the Soul-Soul Fruit could not consume Devil Fruits, because no matter how they were divided, they were still part of the user's own soul.
A single person's soul could not bear the powers of two Devil Fruits!
This was one of the fundamental laws of this world!
If one soul bore two Devil Fruit powers, the body would explode and die—or one of the powers would be expelled.
Unless it was an anomaly like Blackbeard, whose body possessed more than two souls, allowing him to successfully contain two Devil Fruits.
But Vegapunk was, after all, the world's greatest scientist, said to be centuries ahead of the current era in technology!
In the original story, Vegapunk had tinkered with all sorts of miraculous items. He had even managed to replicate other Devil Fruits, and their powers were not much different from those of the originals!
Momonosuke's Azure Dragon Fruit was one successful example...
And Seraphim Jinbe, who appeared in the original story, also possessed a power similar to the Swim-Swim Fruit...
That alone had already broken this world's law—two identical Devil Fruits could not exist in the world!
With Vegapunk, nothing was absolutely impossible!
So, it was not impossible for Vegapunk to take a different path: give a soulless object a soul and turn it into a vessel for Devil Fruit powers!
The Soul-Soul Fruit's power might be capable of accomplishing this feat!
After realizing this, Vegapunk told Yun Ye that he needed his blood—the Bloodline Factor of the Soul-Soul Fruit within him!
This required Yun Ye's consent.
After all, in someone else's hands, Bloodline Factors might not be of much use. But in Vegapunk's hands, they were a formidable weapon...
He could use a Bloodline Factor to replicate a Quincy...
For that reason, Vegapunk needed Yun