I don't know how big your project is nor how intricate the applique is. Can you trim the frayed edges? Then use school glue to hold them in place and then edge stitch or satin stitch around the edges to keep them in place and if the appliques are large, maybe do some addtition quilting in the appplique? If this is a wall hanging, or a table topper, I think it would look OK. If it is a quilt, the back may look a bit strange. How much other quilting have you already done?
I always do some edge stitching around my applique if it is raw edge, adhesives really don't hold well if the piece is going to be washed in my experience.