Can a mom pass on her oral herpes to her kids by kissing them on the cheek even with no blister?

Unlikely. Conceivable but not common. You must remember that most people become infected with herpes simplex at some time in life, and the source of the infection is commonly difficult to identify. Although viral shedding in the absence of overt lesions occurs it would be very unusual to be transmitted, unless kissing on the mouth and exchanging saliva.