One bit of advice and one caution: It's great to look at good onboaring experiences (and bad ones) but be aware that what works well for one mobile app could likely be a disaster for a different one. Think of title sequences for movies, or tutorials; the credits for Se7en were great for Se7en but would be terrible for a romantic comedy, as deep tutorials for Photoshop would be all wrong in tone and interaction for a children's game.
So, basically, I'd recommend hiring a UX/interaction designer! There's someone who does that sort of thing for a living. (Sure, you don't need a degree to be a software engineer, but wouldn't you prefer one to write your code, as opposed to having a graphic designer do it?)