You can. Just head to your user in your User Library and tap the avatar to change it
I've thought about this a lot, which I am considering. The Store is planned to be revamped very soon so I do plan to add this in.
Don't tap the price, tap the product text of the item you'd like to purchase. This has been fixed in next update
Stories are coming in v5.2. Sorry for the push back. But libraries need to be sorted out and improved upon first to bring NEW features and far better stability.
It sounds like a great idea!
In 5.1 - You can use different usernames for Twitter, Instagram and Snapchat
Hasn't arrived in the UK yet. But when it does in March, I plan to look into this.
What device and iOS are you using?
Customer support service by UserEcho