Don't see what the problem is really, Legal formation, players on their positions.... managers choice. Others may not agree with it, but hey ho each to their own.
It's called Freedom of Choice.
Nope.
Formations without Fulllbacks/Wingbacks must be deemed illegal, just like formations without Strikers.
Actually, in real life, a team can win without Strikers, but it can't survive without the men who cover the flanks.