^^ All possibilities (some more probable than others). But a random list of elements I've been keeping in mind:
1) Touko's new insight into who her sister really was (i.e., Touko thought she was becoming a version of her sister, but she actually wasn't. So what's her motivation for continuing to cling to that role beyond the play?)
2) Touko's determination that the play will be the culmination of the "become my dead sister" cycle. Something comes after that, but nobody knows what.
3) The cafe owner's evaluation of Sayaka: "You're a good girl." (I think we can basically trust that, whatever temporary conflict Sayaka may cause.)
4) Koyomi and Yuu revised the ending of the play together, but we have no evidence that Koyomi is aware of Touko and Yuu's hidden relationship. So whatever the import of that new ending is, probably no sex scene, I'm afraid.
4a) However, we did see that particular scene twice and from two different points of view, which emphasized that we still never saw anything specific about what they said or did, so just maybe Yuu did spill a bean or two.
5) Maki's secret knowledge about the TxY ship has amounted to almost nothing so far--dropped stitch, or hidden plot bomb?
I have to say that I'm pretty impressed with the way Nakatani-sensei has set up a wide range of possible outcomes and different ways to arrive at those outcomes (including the possibilities that the whole thing will end unhappily or even tragically, or the opposite) and all of those outcomes could be consistent with prior events and true to the characters.