Hello, Janet. Quick Fire is a nice choice but I thought QF could get much larger than 6'; you may have to prune it to keep it in check. Luis

QF is a 'full size' paniculata, expect it to be in 8'+ range, but as Luis said it could be pruned (yearly!) to desired size.
LLamb...I'm puzzled myself about her size. Bought it from a reputable source to make sure it's not a mislabeled young PG. It was staying in 3-4' range for two years and produced smaller size blooms how it suppose to do, but this year it threw several 5-6' tall canes with huge panicles, absolutely identical to the growing near by PG.
BBride is completely different animal than other two. It's macrophilla and should be planted in z5 at your own risk (read reviews about BB on this board). Based on my observations it will be rather 5x5 than 3x3 plant, but in your climate you might have diebacks that will keep her on a smaller side.
Sunwise, as you describe the location, it would be ideal place for BB and less so for paniculatas which doesn't mean that they'll not perform well there. They might if they'll receive enough light.