The 6th one is still unknown? People thought these top 3 numbers were Ushimaru and the Daimyo?
Numbers aren't all the same imo
Numbers 4, 5 & 10 who were Introduced Together seem to look more Beastly than others, they also lack Clothes.
Numbers 7, 8 & 9 who were Introduced Alone & Separate seem to look more Human but still lack Discipline
Numbers 1 & 3 seem to be Perfect Combination of Oni & Human + Best Disciplined among Numbers
Number 2 on the other hand seem to be like Second Group, Human Treats but lack Discipline
This distinction can be noticed when Yamato entered the Room, only No. 2 followed her, the other two awaited Orders.
So in my opinion, Three Experiments were made to create these Numbers
The goal was to create Ancient Giants who resemble the Original Ones in both "Look" & "Mind"
First experiment created Numbers 4, 5 & 10 who greatly lack both Look & Mind
Second experiment created Numbers 2, 7, 8 & 9 who saw an improvement in Look but still lacked Mind
Third experiment created Numbers 1, 3 & 6 who saw an improvement in both Look & Mind
But they still didn't hit the results they wanted, so all of them were labeled as Failures
I believe the Results changed based on Humans they used in these Experiments
Fodder Humans used in First Experiment
After that, they thought if they used Stronger Subjects, they will get better Results, so they used Giants, but still wasn't enough
So recently Kaido sent them Strong Samurai, and they saw better results but also not enough
In my opinion, True Race Re-Creation can only happen when it's used on someone with Very Powerful Will (CoC)
That's why Kaido was a Success