Just got the cross collision set and was wondering what the legality will be in the mixing of the cores and halfs (ex. One side Hasbro one side Takara; full Takara bey with the Hasbro core)

I misread this originally! You mean JUST the cores mixing.

But I suspect the answer will be No anyway.

---

-----
Hey, parents! Here are all the answers to any questions about WBO Tournaments you might have! Thread-Guide-Hey-Parents-Answers-to-your-WBO-Tournament-questions

Please consult this guide linked below on how to arrive at tournaments before they start! https://worldbeyblade.org/Thread-How-to-arrive-at-tournaments-and-other-events-on-time