Here is a link to a page with pics of all the main characters in Hourou Musuko and their seiyuus, with some info about each seiyuu.
I even found it hard to keep the characters straight in the manga, and the anime starts halfway through the story, so newcomers are having lots of trouble knowing what is going on.
Personally, though, I thought the first episode was the best in the past couple of years. Really outstanding communication of moving situations and emotions.
Click here or on the image to go to the full page: