any white or pastel long sleeve nightie plain, no print, with a blue length of fabric for a veil. get a sequin or plain blue elastic headband at the dollar store to anchor the veil, if it is sparkly it can stand for a halo. sandals or ballet slippers, you can add rosettes also from the dollar store, finish the outfit. she can hold a baby doll wrapped in a blanket, or a rosary
easy costume for any child is a poncho
choose the fabric for the effect you want,
measure from child’s collarbone to just below the knees, double the fabric and cut. make hole for the head and slip it over. find something to tie it with, finish with appropriate decorations and headpiece, done, takes about 20 min, plus time shopping for remnants at the fabric store or walmart
Franciscan friar or monk – brown or grey with a cotton cord belt
nun–black shiny stuff with a white veil and a rosary (brown for a carmelite)
St Joan of Arc–white, with fleur de lis and cross painted on front with fabric markers or even crayons or washable markers–worn over grey sweats or tights + shorts, knit cap for a helmet, add a cross cut from construction paper, plus a plastic sword and shield from the dollar store
St Michael–similar to St Joan, add a shorter “layer” in grey or silvery lining material as a breastplate, make the under poncho red, can carry a stuffed snake for atmosphere