In all honesty the whole Xover only passes small voltage through a Loudspeaker
Everything is converted through the amplifier before the Loudspeaker.
Myself learning well over 20 years ago Electrolytic are by far the worst possible
Way to conduct a signal the only reason used in power supplies normally for is you needed say 10,000uf in capacitance, poly caps are night and day less distortion and noise but are Huge vs same UF- Microfared in capacitance.
In a Loudspeaker largest are in bass caps say 80uf for example.Bass nowhere as critical to the ear such as midrange a decent cap like Clarity ESA, or top shelf for Bass Which I use a Munforf Supreme if in your budget.Duelund way too expensivefor Bass., but for midrange
On a good speaker yes. In a speaker Never would consider leaving electrolytic
All ways a poly cap. Go to magico, yg acoustic,marten, b&w only poly caps
Electrolytic in power supply like my amp over 200k in capacitance,I then bypass with good Audyn .1uf Caps
Poly caps just to clean up the. high frequency noise.This is very common practice.
I just follow what the leading builders do. That being said you do whatever with your monies.