When I re-capped my SP-3005's, I used axial non-polar electrolytic capacitors from
https://qcomponents.ca/
I found the selection of crossover capacitors to be very limited at the regular distributors such as mouser, digikey, etc.
Your mileage may vary, but I think that these old kabuki style Sansui speakers are unlikely to make the difference between capacitor types audible. The real goal in replacement here, is to set the clock back to zero, and allow the crossover to function as intended. They are fun speakers, and very sensitive, but they're not in the same league as more serious audiophile products.
A normal electrolytic capacitor, which is polarized, is intended for DC applications, All speaker crossover capacitors always pass AC, so they must be non-polar, or bipolar. A bipolar electrolytic capacitor is internally nothing more than two polar capacitors connected back to back capacitors in series. In a pinch, you can do this yourself - i.e. teo 10uF polar capacitors back to back in series makes a 5uF capacitor, etc.