These are some nice changes too, and they definitely give me something worth considering.
In the Dawn War pantheon, Garl is a bit redundant with Corellon, Sehanine, and Avandra all occupying similar niches. So if I included him, it would either be as an aspect of Corellon - one of his many forms - or as a powerful archfey, possibly as an exarch of Corellon or Sehanine.
There is probably a stronger case for including Yondalla, but a lot of that is presently taken by Moradin. Hmmmm... Moradin could become more of a Hephaestus deity, focused on creation, labor, and artifice. This would free up hearth and home for Yondalla. Then there is the question of where to place her in the various lineages of the pantheons. On the one hand, having her connected to Melora and Moradin would work because of the myth about the hearth being an ember of Melora's heart. However, having her as the child of Pelor and Erathis would also potentially work, as that could represent the commonality of family and hearths with agriculture and cities, and the hearth may even be the light of the sun gifted to the cities of Erathis. I'll have to chew on this.
As a frequent gnome player, I’d hate to see Garl included at all if it’s as an exarch or aspect of Corellon, but that aside, something to consider:
If your pantheon is meant to be a family tree, and to evoke the sorts of relationships that real world polytheistic pantheons have, overlapping and even “redundant” deities are a benefit, not a drawback.
There should be several gods that that deal with magic, and luck, and fertility, and love, and violence, and travel, and death, but who deal with them in different ways, with different focuses, and with different combinations of “domains”. And there doesn’t even need to be an actual hierarchy between them just because you have 3 gods of magic, or whatever.
But some ideas for old Garl that might help set him apart from Corellon, and make his inclusion do him justice.
Trickery as a retributive act, rather than purely for kicks. A plucky fun loving trickster isn’t the same as a trickster who brings low the unjust mighty.
Gnomes are smarter than elves. Maybe Garl is smarter than Corellon, and thus is a god of deep lore, discovery, inventive inspiration, while Corellon is a god of artistic expression, magic, etc.
Garl is a god with many stories, and in some worlds created gnomes by finding gemstones and telling them a joke. Is there a god of travelers and storytellers?
Garl or Corellon could be be a bit darker than usual, and borrow from IRL Odin, in that Odin is the source of poetic inspiration AND battle fury. Corellon already takes many guises, so he isn’t that far from Odin in many ways. And his son leads the wild hunt!
As to the Raven Queen, I like your take more than the 5e canon take. It’s still more antagonistic than she was before, and I really liked having a fairly helpful if enigmatic neutral deity of death, but it’s very interesting.
Why not flesh that out a bit bit more by adding the Red Witch and The Lady of The White Well from 4e as her sisters, borrow from Nemain and Macha to flesh them out as “Unseelie” without necessarily being “evil”, and have fun with the idea of them being goddesses whose names are taboo, etc.