If Aurelia's system could handle putting up animated avatars for both Clinton and Claire on basically a few minutes' notice, we should assume that this technology is advanced enough beyond real-world limitations that Marigold not having her rig is not a realistic and practical concern. In real life this would actually be a not only reasonable but pretty significant question, but again, in real life Aurelia wouldn't be able to give her children bespoke cow-themed models without prior notice.
Like, being able to custom-build an avatar or use one via procedural generation is a pretty big lift. Usually these avatars take a lot of time and effort to make.