Don't go by these numbers. Remember, power does not destroy speakers, distortion does. So it is easier to damage a speaker with a small amplifier than with a large one, because a large amplifier would produce the least distortion. So you need not base your speaker selection on these parameters. The criterion here would be to select an amplifier that has a power rating greater than your speaker's maximum power handling capability.
Frequency response is the frequency range that a speaker can reproduce.
Most speakers can and do go up to and beyond the 20kHz hearing limit. Most tower speakers go down to 30-40Hz. So any decent speaker should satisfy your desired frequency response. Impedance is the measure of the resistance that a speaker puts on an amplifier. So you have to be very careful to match the speaker to amplifier impedance.