I've just finished my first year at uni. Recently a friend back home told me it's illegal not to have a student bank account if you're receiving student finance.
Student Finance Wales have never raised any issues with me using my old current account.
It's not a legal requirement, just a nifty way to incentivise you to give them £15-£18k in loans to look after over the 3 years or so (which they can make money from) whilst giving you some offers such as a railcard or reduced rates on an overdraft.
It's up to you to take the offer, but it's not a requirement.
Never heard of that at all. I was at uni for a year and a half and I never had a student account simply because I wasn't 18 until halfway through first year and then kinda forgot about getting one.