The style is very similar to Dragon Quest IX in which customization is available so hopefully they'll include it. It's quite difficult to give a detailed design to the characters of modeled like that. I doubt they have any big trainer sprites like in previous games since they wouldn't fit with the style of the game. If there was Sugi-style artwork of the protagonists, it'd probably be really plain. It's also odd that it wasn't included in the video. So yeah, I'm really hoping for customization here.
EDIT; As glitchguy mentioned, the protagonist looks suspiciously like Hilbert. Also, if you look closely at the video, the girl seems to have a very similar hairstyle to Iris in another colour. And also, the girl that's following the protagonist in the video has May's clothes and Rosa's hairstyle. Extremely suspicious, haha.