Given the team theyare taking I'd say it's fairly certain that Richel will play singles along with Arantxa and Chayenne and Nicole are both ranked way below. Nicole will probably get to play doubles - perhaps with Richel. i have the sad feeling that Chayenne is just "making up the numbers" and probably won't really be used, but I might get a surprise.
Chayenne is the best double player so it would be very strange when she is not playing.
Actually, I think Thyssen is better but seeing as she was injured most of last year and hardly played, her rankings have gone to shit. I hope they do use Chen and nicole for doubles, but it wouldn't surprise me if they don't.