Juliet comes from a wealthy family. Wealthy families back then had lots of servants. Juliet's personal servant is the Nurse. The nurse basically raised Juliet from infancy. Fed her, bathed her, clothed her, taught her, etc. That's a lot of motherly characteristics. It goes deeper than that though. As Juliet grows up, the Nurse becomes her mentor and confidant. The Nurse is a bawdy, sexually free woman, which is likely the reason that she helps Juliet early on have a secret balcony rendezvous with Romeo. I'm not sure a mother would help do that, so maybe not too motherly there; however, later the Nurse attempts to convince Juliet to forget Romeo and marry Paris. The Nurse knows that Paris will be a good provider for Juliet and will make her family happy. That DOES sound like something a mother would council a daughter toward.
Friar Laurence as a father figure to Romeo is a bit more of a stretch than Nurse/mother to Juliet. The friar IS a mentor to both Romeo and Juliet and DOES give them the advice to be more cautious. In other words "Take it slow Romeo." That does sound fatherly. I'm not quite sold on believing that the friar has the utmost well-being of Romeo and Juliet at the forefront of his thought though. He DOES marry Romeo and Juliet. I guess that could mean he is making sure that they are happy together, but a main reason for him performing the ceremony is that he thinks it will end the feud between Capulets and Montagues. That seems manipulative to me. Like he's using Romeo and Juliet as pawns, so not the most fatherly image I can think of.