Will the shasta daisy re-bloom or is it just once a season?

Shasta daisies will rebloom several times a year if you deadhead (remove old flowers) correctly. I cut the stem above the node closest to the flower before the flower is spent and has a chance to seed; the node will produce new stems that will produce blooms. If you remove those flowers before they go to seed, the daisy will produce even more stems - and it will continue to do so until you allow the plant to go to seed.