I'll take this here so we're not cluttering the FC thread.
Ken likely won't be a Lieutenant -- I'm aiming for one of the Seated officer positions, because I feel that'll allow him more freedom when it comes to availability. I'm actually hoping to port my version of Hisagi and possibly have him as Co-Lieutenant of the 9th. But that isn't decided yet.
That doesn't stop either Takeji or Ken having a rapport though. From what I can gather reading Takeji's article, he likes a good fight. Ken was a former member of the 11th Division so he likes one too. Maybe a relationship similar to the one Ikkaku and Iba demonstrated? Friendly sparring matches and the like?