Looks like Mertens/Wacanno won't need a WC.
These teams seem to have entered doubles:
HLAVACKOVA, Andrea/BABOS, Timea
BERTENS, Kiki/SCHUURS, Demi
OSTAPENKO, Jelena/KALASHNIKOVA, Oksana
MELICHAR, Nicole/SMITH, Anna
KICHENOK, Nadia/KICHENOK, Lyudmyla
GEUER, Nicola/KUNCHIKOVA, Lenka
MERTENS, Elise/WACANNO, Eva
KHROMACHEVA, Irina/KALINSKAYA, Anna
GARCIA PEREZ, Georgina/LISTER, Cornelia