But it was already mentioned in the ep description, so why not show something about it?

And has it ever happened before that there were two DC?

The promo, and both DCs all about LL/C.
I really like LL, but I miss Emily/Richard more. And I don't think there will much about them in the next ep, maybe only the short bit at the end with Richard collapsing.
Because there's already Sookie bribing Lorelai with Luke's coffee, the flatscree scene with Lorelai/Chris, the scene with Luke/Anna before curt, then there must be one with Chris finding the letter, while showing the court again, and the one with Lorelai and Chris fighting, maybe one with Lorelai watching the kids actually, so that doesn't leave much room for anything with Richard before he's going to collapse.