Right know i doubt that he did that unknowingly tbh
I actually doubt that Kuma would have captured Luffy for the WG on Thriller bark ,he tried to bring him to Dragon i think.
After he saw what Zoro and Sanji where willing to do for Luffy,he knew he was in good hands .
At Sabaody Kuma send them to places which he thought would suit them best .
This man got a plan since Thriller Bark