If the consent of the guardian is not required based on his religion, it is permissible to marry his virgin daughter without his permission. The permission is also not required if the father mandates his daughter to deal with the matter of her marriage.
If one piece of clothing is najis, then washing it with tahir clothes makes all clothes being washed najis even if detergent is used. They do not become tahir again unless they were washed with unmixed tahir water.