really, when I said initially that I was worried that they'd over-emphasized Katara's "Aang color scheme" over his references to her, it's because I can already sense another decade's worth of discourse a la the "why didn't Katara get a statue, is it because her husband abused into a stay at home wife with no accomplisments???" type of discourse (and also because of course Aang should honor her appropriately, that's obvious!)
Now looking at it, Katara wears a yellow string in her belt and a small band at the tip of her braid. Meanwhile, Aang has updated his pendant with blue beads to honor Katara.
The discourse I worried about is already rolling, likely exacerbated because Aang's reference to Katara isn't visible or properly saturated in the like 2 out of 3 leaked pictures we have of his design. It is likely to be much clearer in the actual movie.
If you actually consider it, Katara's design shoots down a whole lot of nonsense discourse that her being with Aang would somehow take her own culture away from her. She is fully dressed as herself and as an adult watertribe woman - she wears blue from tip to toe, fully traditional watertribe clothes and watertribe hair including her own hair loopies. She wears a pelt, she wears her mother's necklace. There's nothing significantly "air nomad" about her design.
The two pieces of yellow bands that honor her husband are mere accessories with no deeper cultural significance, absolutely nothing that marks her as "belonging" to Aang's culture, nor are they diminishing or even interfering with any aspect of her own identity.
On the other hand, Aang's honoring of Katara, while maybe slightly less eye-catching (specifically so in the art that's been released) are actually far more significant representation of Katara as included into his culture.
That pendant is the most spiritual thing Aang wears; it represents his own growth and his attachment to his lost nation, with him as it's sole living representative. He wears it all day over his heart! The fact that Aang added Katara's colors to this item represents how she is the love of his nation reborn. Like Aang really wanted to wear something of such dignity and meaning that represents how Katara is integrated into his very identity and being.
In the film, it's likely to be very visible in most shots that include his face/body, except for close-ups. It's actually far more significant that Aang decided to include Katara into his most significant item, one that specifically represents his own culture so intimately, rather than her simply wearing a few yellow strings as somewhat superficial accessories to her own watertribe outfit.