Names for my unborn twins?

I'm 6 months pregnant with twins but my husband and I decided not to find of the sexes of the babies. So, basically we have to prepare 2 names for each gender. We really like Luca and Jagger for a boy and Valentina and Scarlett for a girl, but we're not sure. We want a unique name yet something everyone can pronounce (my mother's German, my father's French and my husband is American). We thought maybe Valentine instead of Valentina so that my French relatives can pronounce it. What do you think? Any suggestions?