Those answers are actually not obvious, when it comes to YA and younger. (I saw the listing in Pub Weekly, by the way.)
We hired an external publicist specifically for our children's line because of the specific challenges of the children's book world, and I highly suggest your company do the same--consult an expert who has contacts in the community. I could tell you all sorts of places, but it won't be the same as an expert in children's publicity/marketing.
Reading your last paragraph closer, sounds like you've got someone for that. That's a good start.
Genre-wise, I don't know as much as about children's, because I work specifically in the children's market. Children's fantasy really doesn't get covered in the genre markets unless it's famous enough to get cross-genre support. However, Locus just did a YA issue--that mention of my own anthology was in that issue--and they actually did a good job of explaining to a more general audience what YA is.
But as far as YA outlets, you should start looking into the review outlets for YA--School Library Journal, Horn Book Magazine and Guide (they require them to be hardcover for reviews), Kirkus. There's also a number of online outlets you should look into. However, I don't have an exhaustive list here at home (we get off early on Fridays nowadays).
So, yes, pump your outside marketer for more info, but also consider hiring--even for a short-term consultation basis--a PR person who specifically knows children's books. That'd be more likely to help you get a full spectrum of specific information for your needs.
