I had a theory about the Snarl...

[Ironsmith]

And that took on the appearance of a big claw reaching out from the rift and stabbing her? I don't find that particularly plausible.

That happened in a crayon flashback, which implies some degree of unreliability and stylization.

Also, when the Snarl attacked Laurin it also stabbed one of her soldiers. Was he also studying the rift?

Maybe, but probably not. Not that it would matter; if Laurin's study pulled a part of it out through the rift, there'd doubtless be effects on the immediate surroundings.