My girlfriend recently got her beta key, so we thought we'd try out multiplayer. It let me invite her to a match, but only my three figures dropped on the board. She had no figures and no hand. Either the default party didn't load properly, or it should have prompted her to make one.
She'd done the campaign to level 4, and it still didn't load her characters to multiplayer. Possibly a bug with the new "save/retrieve"?
Unless she created a specific mp party in the mp keep, she won't have a party. SP party doesn't automatically load into mp if you tried a casual match. You're probably aware of this (and it's likely related to the store/retrieve feature as you say), just making sure.