In the Outside World, there have been recorded cases

of brain cells continuing to function for more than ten minutes after death.

In other words, if her body was very well preserved...

If an anti-rotting spell was cast on her immediately after death, it could be possible for those brain cells to remain dormant, and then reactivate when she turned into a tsukumogami.

It's not that impossible. After all, once you get to the root of it, memories are just another part of biology.

But... some points remain a mystery. Such as her memory.