Yeah, I agree with you about the last two cases. The details kind of blend and muddle together for me. For all the talk that 5-4 and 5-5 should've been one case, those two are clear and distinct to me.
The Ryutaro thing was just an excuse to have another intro case in Japan. I really don't think Takumi thought about it beyond that.
https://imgur.com/WqDcNNq
https://imgur.com/89Z5jrB