I decided to take a super-close look at the last scene to see if I can squeeze some of my OCs into an actual shot. (I am petty. I admit it.) I plan to stick Carlos and Calles and Tina in there regardless, but there are no likely candidates that we saw, so they're, you know, in the kitchen eating Elena's tamales or something.
But here are some others:
Is it me, or is the younger woman here the woman who hosted the talent show at the plaza the year before? Don't know who the older folk are. (There was another child in the papel picado stuff who could have been a brother of Elena and Victoria, but it's too late to add him at this point, and no canon source ever mentions that, so I'm assuming this guy is someone else. Maybe they could be Luisa's grandparents, who've been driving around in their RV all year?)
I think I can pass off the woman in the purple shirt and jeans as Tia Meche, and maybe the woman is her daughter Leti? The girl could be a variety of cousin.
I'm declaring this dude in the cowboy hat to be Papa Ysidro. No theories on the woman in the shawl.
Another cowboy hat dude talking to an apron lady. No theories, and they're actually on the street outside, so they may not be involved.
These two are talking right outside the big gate that leads into the residential half of the hacienda.
I thought at first that they were these two, seen from another angle, but the clothes are different.