I'd stay with small for all of your speakers, definitely. The -3dB point for the B&W 804's is around 38Hz, so you might go with either a 60Hz crossover or the 80Hz you are using now for the fronts. The -3dB point for the HTM3S is 42Hz, so 80Hz is a pretty decent choice there, as well. The -3dB point for the DS7's is 80Hz, so you might even try a 100Hz crossover for the surrounds.