I think that, this way, you avoid fans disliking name choices. If the names were revealed and they were named after dead characters, some fans might complain that it's unoriginal or that it would put pressure on the kids. If they weren't named after people, other fans might say the dead aren't being remembered or honoured. Some fans might just dislike the names themselves, or feel they're not different enough/too different, or don't follow a pattern or something.

I know some fans would prefer that they create the names for unnamed characters, but I am not one of those. I think they should have had names chose by the author.

^ I completely agree. I think Suzanne Collins confirmed that the names were Willow and Rye.

When did she confirm those? I thought they were popular fanon.