Bypass capacitors in crossover circuits are, in my opinion, useless. The reason bypass capacitors are used is to lower the overall impedance at frequencies where the equivalent inductance of capacitors has the dominant impedance, which is above the resonant frequency of the capacitor’s inherent RLC. That frequency is way above the audio range.
If you take, say, an exact 10uF crossover cap and bypass it with an exact 0.5uF cap, all you have is one 10.5uF cap. However, if that 10uF cap has a tolerance of 5%, then it can have a 10.5uf capacitance on the high side. Which is exactly the same thing as the 10 plus 0.5 cap in parallel. So I don’t see what benefit piggybacking a cap does to a crossover.
In power supply circuits, the RFI can easily exceed the resonance of the filter caps. That is why bypass caps are used, to lower the overall impedance at those frequencies to shunt the noise to ground.