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. 8 ohms is the standard, but most receivers are built to withstand impedance loads much lower than that. Don't pay much heed to other parameters such as timbre matching and decibel sensitivity. All manufacturers design their speaker to sound tonally the same. Interconnects and speaker wires can enhance or hinder the system performance.