According to this site, SW:TCW supervising director Dave Filoni says it was complete coincidence. Although he admits that it's a pretty odd one.
On Moulin Rouge References
Filoni: It was the funniest thing... I had no idea that people drew a connection between the Ewan McGregor is Obi-Wan Kenobi [thing] and the woman being named Satine. I didn't realize that at all. I called Henry Gilroy, who named Satine, and asked him, "Hey, were you aware of this?" And he said no, that he didn't really think about it. And I was like, "My gosh, do you know what people are saying all over the place about this trailer?" It had nothing to do with that. I guess it's just synergy? I don't know. It's very bizarre. I still wanna question Gilroy about that, because I'm like, "Come on, really? I mean, out of all the names, really?" It's pretty weird, I'll give you that.
