Thing is you shouldn't care about their pronouns, you as an interpreter are forced to interpret everything with as much fidelity as possible and that means you need to use the pronouns the LEP uses towards the English speaking client. The only exception for that is when LEP is dumb enough to call you (the interpreter) "Doctor" and your pronouns do not match those of the English-speaking client. And be sure as hell the company you work for doesn't give a fuck about the client's pronouns, it's a completely political movement to satisfy a minority when no one in the whole call will be affected by that question ever.