Honestly, I know very little about the toy market myself. But it would be an interesting case to work on branding-wise. If you'd like any help with naming or even pitching (from the standpoint of written copy), let me know.

Unless the physical toys themselves are radically unlike others on the market, then I think you'd be smart to differentiate your product line by developing the STORY first and foremost. That way, you could elaborate your premise and characters.

Whether that story is presented to investors first (in a pitch deck, let's say) or to children (via graphic novels, cartoon shows, or TV / video ads), it's the story that should sell the merchandise.