This brings me back to another site where someone brought up the names: Raunchy Ruby and Sexy Sapphire, which I thought was hilarious, despite them of course not going to be choosed because of the nature of the first words. XD
Anyways, I'm not sure what to expect, although I do think words associated with land and sea would fit best(since GSC/RBY didn't have much of an opposing theme).
The fact that they thought up Heart and Soul for Gold & Silver, it's slightly relevant but it's totally unexpected so you can assume the same for these two for those who are expecting Magma Ruby & Stormy Sapphire.
Well yeah, they were slightly relevant, but neither was a 'best fit' sort of name. They could surprise us with something else, but it's hard to think of them passing up something really related to the theme of the games.