the toilet seat is remotely possible but girls using the toilet typically do not have these parts directly touching the seat. if the herpetic lesions were on her buttocks or legs it would be more possible. you cannot get or transmit genital herpes by drinking or eating after someone. just direct contact. as long as she keeps her hands clean after using the toilet and of course keeps the bathroom toilet spotless you will be safe.
my daughter has genital herpes can we 'catch' anything from her by drinking or from the toilet?