KDEY is, for general market ratings driven broadcasting, licensed to an area that is not rated. That area from the LA County line along the foothills from roughly Fontana to Rialto is not in the IE book or the LA book. The signal does cover pieces of the LA market and the IE market. The significant niche there is Mandarin speakers.
The LA signal is broadcast from Baldwin Hills, and offers pretty good coverage of much of the Black, African American and Korean populations, among others. It's not a very good signal for non-Hispanic whites, although it does cover the Westside and the coast from just north of Long Beach to Pacific Palisades fairly well.
My guess is that, based on coverage and the wealth of the market segments, Mandarin would be the best choice on both signals. If not, Korean on the LA signal and Mandarin on the IE area signal might work. Caveat: I have not looked closely at population data for Asian nationalities / heritage so this is more an impression than a conclusion.