Your daughter was, according to your post, not arrested or charged with shoplifting. From what I got out of your post, a criminal trespass warrant was sworn out against her. And there is nothing whatsoever illegal about that. The shop owner, however misled, is well within his rights to bar her from the store.
The officer also was correct in that he had no right to conduct a search. One, because he was a male and two, she was not being charged with shoplifting.
Now, that being said, I would strongly advise you have a 'come to jesus' with your daughter. Not because I think she was shoplifting then or earlier (although I think it's a strong possibility) but because any further action by you in this matter is contingent on her being truthful, completely.
If you are confident of her honesty, then make an appointment with a competent attorney first thing Monday Morning and file a civil suit against the manager personally, the store and the employees who detained her.
Discuss with your attorney criminal intent provisions of Illegal Detention
It is, first, of utmost importance to emphasize that the detention of any shoplifting suspect should be based upon first hand observations by the merchant or his/her responsible, authorized agent. The intent of the suspected shoplifter must be clear, preferably including such elements as concealment of the item(s), nonpayment in any manner, furtive actions, and leaving the premises. These elements combine to show criminal intent and thus, probable cause to detain/arrest. (1) A shoplift detention lacking strong elements of probable cause, as mentioned above, may be a weak criminal case and certainly would be an ill-advised civil restitution claim. The apprehension should have no legal flaws.