[Gohan78]

Originally Posted by Vena

The problem with the key interactions, particular the date in the sky, is that they were always (or almost always) Amata chasing Mikono or Amata doing something.

Well, in this kind of series usually it's the man who must chase the woman. But Mikono's reactions to Amata's advances are significant. She blushes and accepts him. I think that without Kagura's intervention they would have kissed during the "date in the sky".
OTOH when Kagura tries to kidnap her she either faints or resists with all her might while she calls for Amata.

Mikono does not pursue any relationship (the flower of everyone's affection) but still gets jealous when someone tries to... do something assertive.

She is no different from many tsundere anime heroines (Shana, Louise, Haruhi). They never admit that they love the MC until the very end, yet they are clearly jealous of him.

For one, I don't think she cheered up Zessica on the beach. I don't think that was what that scene was meant to convey... and it certainly didn't do any cheering up. So if that was its intent, it was a catastrophic failure.

I disagree. At the end of that episode, Zessica was cheerful. She decided to change her dress and apparently challenged Mikono for Amata's love.
(Let's forget that in the following episode she became depressed again. That's just one of many inconsistencies of the writers.)

Mikono's been kidnapped once, effectively, by Kagura, three episodes ago. His small interruptions every 6 odd episodes is not a reason or excuse for her doing nothing and never sitting down to talk with Amata.

I think that the lack of communication is the only thing keeping Amata and Mikono apart. It's also a terrible plot device to keep the love triangle unresolved until the last episode.
But in all honesty I don't think that one can look at Mikono's reactions towards the two male antagonists and say that she is undecided or that she wants "the best of both worlds". She evidently chose Amata. She is just too shy to confess.