All rightee -- based on my understanding of the hammer space as being effectively a black hole brand of magical storage where characters can pull things from: they're welcome to retain the ability to store in that way, but they should come with very minimal stored inventory. This is just to avoid giving anyone too huge of an advantage. So let's call it at most five stored things of small size (portable).

You can have one of the robots, but not two — Sigil would not qualify.

Karla's problem sounds solvable in the way you referenced. Skuld sounds potentially too bound to the canon home world to be workable, at a first read.

I hope I got everything & there are the rest of the app guidelines in the app form, if that helps!