Would need to consider what else in the contract may restrict what she does.
Morally (a) is wrong. Also, your daughter has a duty of loyalty to her employer and poaching clients can be considered a breach of this duty, and therefore potentially actionable by the employer.
wrt (b) as long as she does not solicit the customers and there are no contract clauses prohibiting her moving to another employer, she will be on safe legal ground.
Keep in mind there can be a fine line between solicitation and advising a client you are moving to another employer. She should not even hint at saying the client can follow her. So while a client is free to get massages where ever they want, your daughter is not necessarily free to say follow me.