They have the username already, they don’t need to see their profile info to search for a username

Just a one time purchase. Op probably meant they have bought 0 pokemon games but bought this

Yes and please make sure you get it checked out! It may seem like a non-issue (just minor pain, etc) but if it ever gets worse the damage is likely going to become permanent and your quality of life with no teeth/extreme toothache is a lot lower than you might think.

Source: my dad and uncle neglected their teeth and its becoming a bad issue now