I mean, the original Riku Replica in Reverse Rebirth had Soul Eater since the moment he was born (even using it in his first battle with Riku). That's because he was built using a lot of Riku's combat data, so he he's pretty much got Riku's physique, as well as all of his powers and "talents" (possibly gaining even further enhanced copy abilities from absorbing Zexion's power). Similar to how Xion was able to mimick Sora's Kingdom Key and other abilities back in 358/2 days.This now makes me wonder how Organization XIII Riku Replica got a Soul Eater...