Felt like sharing a little backstory on Shalla-Bal too since most of the audience will end up assuming that she's a simple gender flip of Silver Surfer. She first became a herald of Galactus in What If? #37 from 1982, but she wasn't silver and her name was Starglow as shown from a page from that issue included below.
It seems fairly clear from what we've seen so far and from what we saw in the Thunderbolts after-credits scene that this version of the Fantastic Four come from a different universe than the 616, so having the film's herald also be Silver Surfer's wife from an alternate universe story seems like a an intentional congruence.
IMDB isn't calling her Silver Surfer so we'll have to wait and see how they refer to her in the film. Similar to the way that Multiverse of Madness never referred to Shuma-Gorath verbally since they lost the rights to that name I'm guessing they never call her Silver Surfer in the film at all, and if they had made her gold/yellow like they did in What If? then most fans familiar with the comics would also mistakenly assume she was Frankie Raye instead of Shalla-Bal.
We'll have to wait and see how the film actually handles her. Seems like they intend her to be a mix of Silver Surfer and Starglow, but maybe that ends up being wrong and we get a fair amount of back story for her, who knows.