I haven't used Dream battings yet, but have always heard good things about them. One thing to consider is that it is really not necessary to use flame retardant battings in quilts. A quilt is not going to go up in flames the way a nightgown would, because the quilt is thick. Nightgowns are a flame hazard because air is accessible to the fire from both sides of the fabric simultaneously. The thickness of a quilt means that less air is available to flame, so a fire will move more slowly through it.
There is a trade-off with using flame retardant batting, and that would be the chemicals in the batting. These chemicals are worth the trade-off in loose children's PJs, but not IMO in quilts. If a quilt starts on fire, you have time to get it away from a child. With loose PJs, the child is engulfed in flames before anyone can move. So, my choice for a quilt would be the 100% cotton batting. Cotton gets softer with every washing too. As for the treated batting, the chemicals eventually wash out. With the amount of washing that a child's quilt gets, my guess is that flame retardant qualities typically last less than a year.