Regarding your story. There's one slight slip. Better correct it before
it gets worse.
Colonge does know Ranma knows Shishihoukoudan. Check vol 20, where that
attack makes its first appearance. If you have it.

Err... Ranma can't do the Shishihoukoudan ... he does the moku<whatever>,
which isn't anywhere near as strong. If Ranma does the shishihoukoudan,
Cologne wouldn't know he could do it because he's never done it before.

Kun-chan...

Moukotakabisha?  ^^;
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* Mihoshi