I love being able to just reference part 3 for Diane / Susan stuff now.
I anticipate two fair questions that I'm not bothering to address in the comic itself for the sake of pacing, but I will address them here:
1 - Shouldn't Elliot know why Ellen's nervous? He didn't consider that aspect of it right there and then. Not a huge mystery, but it's a fair question and I didn't have him say "oh, right" or anything to acknowledge him knowing about it before (would've clashed with the "half-sister" reveal), so bam.
2 - Why aren't Tedd and Grace all like "sisters?!" right now? They were told about the twin possibility before Nanase and Mr. Verres joined them downstairs. Once they were all down there, however, it was on to other business, hence Ellen not yet knowing about the half-sister theory.