If Jade is permanently closed off (as I suspect, given how Cathy is auto-cutoff as well), it's probably for some sort of play balance reasons; keep equivalent content on different 'paths.'
That said, Jade is a rather vindictive woman. I can see her being pretty pissed when the MC leaves her hanging, especially since the whole point of the tryst was to prove she was still sexy and desirable. The fact he has a 'legitimate' excuse just isn't relevant from her end. (And heaven help the MC if she learns the real reason!)
The preview pic. Jill playing the piano in full formal dress is hard to explain otherwise.
We never learned exactly when the concert was supposed to occur:
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It's obviously in the near future, but beyond that it's hard to say. The MC's response implies it's still a ways out, but then again he though his birthday was too and that seems to have been a week away. Given this was back in Episode 3, it does feel like enough time has passed out of game to pay off that plot plot thread so I'm adding it to the list.