This is one of those 'perceived wisdom' things that is a complete crock of shit. Formation and selection is not tactics. If you understand players attributes, what you as a coach want of them, show them how to play that, and get their buy in to actually give it a proper go, then who knows where they will play.
You speak to a fan, and they will say things like 'we have to play 4-4-2' and he's a 'right winger' or 'can play number 10’. Lazy. Dim.
Speak to a player, or a coach, they will tell you what a player can do. 'Left foot, right foot, can go on the outside, good acceleration, not a great engine, quality delivery from wide, not good in tight spaces'.
A good judge, coupled with good coaching and management, will take attributes of a player and utilise them, with player buy in, to work on a position, and improve attributes for the position (consider how TAA has improved defensively this season).
A lot of thinking about football these days is like modular building blocks. Plastic Lego football. Getting the block you need, and using it exactly as is. It don't have to be that way - although the lack of patience and restricted transfer windows mitigate against actual building. What modern football has is commoditisation of the football experience and all it's building blocks.
The days of taking a washed up troublemaker striker, and turning them into the best defender in the country, are probably over. Not because it wouldn't work, but because it doesn't fit the modern state or criminal enterprise ownership financial model of former community assets.
Manure can't currently buy a competitive team in the timeframe that saves a coach their job. Not in off the shelf modular parts. So to be successful he's going to have to do some old fashioned coaching and team building, and get some of what he's got to run in different areas, and kick in different ways.