Isn't ZuiZui is a another pairing came together for the dance? You're not one to suggest here "rival Zuihou".

And Zuikaku is harem lead much.

any historical basis about the relationship between Zuikaku and Sendai? Or is it just because Zuizui mispelled her name in her hourlies?

Shebadotfr said:

any historical basis about the relationship between Zuikaku and Sendai? Or is it just because Zuizui mispelled her name in her hourlies?

I think their only connection is the fact that in one of Zuikaku's hourlies (or Sendai's) Zuikaku is yelling at her to shut up at night.