Going off how I've said they need to commit to some kind of trinity of fairy tales / literary adaptations (whether books, legends, whatever), trying to think of the best ones to go with.
- Rumpelstiltskin is one of the best-known left that doesn't feel too inconsequential but also gives them room to work with. A story with a protagonist who makes a deal with a villain seems appropriate for first in a trio since it parallels both TLM and TP&TF in the last trio of films that revived them. With a flip on TLM, the female protagonist makes the deal to save her family that's destitute rather than out of discord with the father. They'd have to work on whatever the "price" would be since of course it wouldn't be her firstborn child like the tale. Perhaps the deal elevates her to being in the castle and her price is giving Rumpelstiltskin inside knowledge about whatever the King (or Queen) is doing--or whatever their weaknesses are--in order to help him overthrow the king/queen eventually unbeknownst to her when she first makes the deal. Perhaps some buddy roadtrip with a prince love interest to find out Rumpel's name and defeat him after he's taken over with him sending some kind of magic or creatures after her and the prince to stop her similar to Facilier sending the shadow creatures or Ursula trying to stop the kiss with the fake wedding? Maybe the Prince met her before she was helped by Rimpel and Rumpel's magic disguises her from him. On the roadtrip, he'll naturally distrust her to begin with considering he thinks she helped Rumpel only to grow close to her over the time whole being conflicted over the girl he met before (similar to Eric's conflict or Naveen's evolution towards Tiana).
- I wouldn't mind them reviving Gigantic after the last concept art we saw of it was surprisingly pretty interesting. Plus, it's best to have at least one of the three be a story with a male lead. I could see Gigantic fitting here in the second of a potential trio since the giant child they described in versions they had worked on reminded me of Rapunzel wanting to leave the tower and Jack is a bit Flynn-esque; it would be better to make the child older for the sake of a romantic plot. To parallel B&tB and Tangled, they could insert a villain in the vein of Gothel / Gaston who is the type whose darker side is only revealed to the protagonist(s) as the story moves along. Perhaps the giant who had the goose that lays golden eggs or whatever person gives Jack the beans. If a giant is the villain, perhaps them being defeated could somehow make all the giants normal-sized or something along those lines. That's the only way there could be some kind of romance between Jack and the giant character (the size differential at the start would remind me a bit of the hijinks of Rapunzel with the frying pan). Perhaps the road trip or whatever aspect would be Jack convincing her to take her to the golden goose for some reason. Just thinking as I'm writing here: Perhaps if the villain is whoever gave Jack the beans instead, they would be a bit like Jafar with Aladdin--asking Jack to retrieve the goose in return for helping Jack save the mother's farm and keeping them from starving. Actually, that sounds a lot like early Aladdin and "Proud of Your Boy."

Unintentional, but I like it. Perhaps taking the goose away transforms the giants normal-sized and returns them to wherever Jack is from which they had escaped from. Some kind of jeopardy they're put in because of it gets resolved, they get the goose back (maybe the golden eggs are some kind of wish-granting thing that had made them giants and allowed them to live in the sky, IDK), but the giant heroine character convinces them to stay the way they are rather than going back to being separate from the people below. That would work if her father was a king and the one who had the goose they steal, I guess. Her finding out he tricked her initially to get the goose would be reminiscent to Rapunzel thinking Flynn abandoned her for the tiara and feeling betrayed, with him having some kind of near-death in the climax for her sake as a resolution? Similar to Beast/Flynn dying. Him dying could be what makes the former giants decide to stay, and maybe a golden egg revives him or something a la Rapunzel's powers doing it for Flynn.
- Hansel and Gretel could work if they gave it a sort of Coraline-vibe maybe. The sibling relationship being the focus would be reminiscent of Frozen. The witch snowing the two children and manipulating them is also Hans-esque really, but of course it wouldn't work as a twist for the audience like Hans did since the tale is so well-known. They'd have to work to make this one more substantial. Perhaps H&G are an orphaned prince and princess, and the witch is a character who comes to court attempting to manipulate them with gifts (toys, food, etc.) out of desire to takeover somehow. That would also parallel Jafar's Vizier role manipulating the Sultan and Hans trying to use Anna. Hansel would end up falling for the manipulation (similar to how he's the one that falls for temptation in the tale), causing a division between the two siblings that grows. Maybe the family has some kind of secret power source the Witch is trying to get at (to "consume," in other words) that they don't know that she knows about, Hansel reveals it to her at the climax after the division between him and Gretel has reached its nadir, then naturally the takeover and battle occurs (with Gretel having to do her in to save them both a la pushing her into the stove in the story). Again, just brainstorming as I go--maybe they aren't the orphans they think they are. Perhaps they learn in the climax (maybe Gretel learns via some roadtrip scenario she goes on to find out more about the Witch with some Kristoff-type love interest just before Hansel makes the decision to show her the power source, giving some kind of race sequence to get to him only to just fail to get there in time or he simply doesn't believe her when she gets there) that their parents had been abducted and transformed by the Witch when they were on some trip or other because two children would be easier to get past / manipulate than adults who know better. That way her death restores the family at the end, Gretel has her love interest, etc. Perhaps the Witch's relationship with Hansel could be reminiscent of the White Witch and Edmund from Narnia, playing on sibling jealousy or whatever, her trying to be a maternal figure to manipulate his grief over the parents for her benefit. Maybe the Witch isn't even a person really, but some kind of dark entity naturally drawn towards the power source.
All three would be stories you would know right off even if they had weird adjective titles or whatever. As far as music... The Lopezes were already part of Gigantic. Either they or P&P on the others. Particularly on the latter, if they gave Gretel a sort of Jasmine-esque desire for freedom (that also parallels Elsa/Anna both hating their lives in Frozen), I could hear something like "Waiting On a Wish" working there. But Miranda wouldn't be terrible since I liked Encanto's soundtrack. I expect both he and the Lopezes would be busy with Frozen, Encanto sequels to do more than one original project. What is Stephen Schwartz doing these days anyway?