Hmmm... I can't believe the steam cleaner didn't help .As far as the white stains, that's why it's important to test a small, inconspicuous spot in case it messes up the cloth. This way you don't ruin your entire seat. I would take it to a detailing place and see if they think they could get the seats clean.
2009 Liquid Platinum Metallic Vibe GT - 5-Speed Auto – Garage
2009 Steel Blue Metallic Vibe GT - 5-Speed Auto – Garage