I would like to upload a sticker pack of the brand. My question is: will Apple has the exclusive right to that pack?
Will I be able to continue using it in other messengers and web-sites?
For questions like these, you should always have your legal representatives refer to our Developer Program License Agreement. The current version that you're team agent has accepted is always available in the Member Center under the Membership section.
The safe answer is obviously check your license agreement, but I don't think Apple would want to deal with some kind of hidden exclusivity agreement. Think of all the apps / games that are on both the App Store and Android store (whatever that store is called). You think if Coca Cola puts out a Sticker pack, they are agreeing to only ever have iOS stickers and relinquish using the Coke logo on their website. Really doubt it =)
