UES is a signal level part. UDB is for speaker crossovers but is to be discontinued. Status now is last chance for lifetime buy before they are gone.
https://www.nichicon.co.jp/english/series_items/catalog_pdf/e-udb.pdf
https://www.nichicon.co.jp/english/series_items/catalog_pdf/e-udb.pdf
Ripple current is AC current and so is an audio signal. So yes ripple current is a relevant parameter for crossover capacitors. I don't know if it;s an exact correlation, but in general purpose made crossovers caps should accommodate whatever current might flow through them for their rated voltage.
Assuming the bias is the correct polarity, consider that zero-volt bias is not different from the component shelf life. The feedback decoupling cap in typical amps is a common failure, but they are often under-voltage, ie 6.3V or 10V when potentially exposed to maybe 50V from the output. Clamping diodes can provide protection. Latch-up can occur when a high DC output voltage reached the amp input. Bias servos may or may not solve such problems.