I will give my thoughts on Brazil
In 2002, Scolari played a 3-5-2 (his favorite formation). It's a very defensive formation, but he had Rivaldo, Ronaldo and Dinho carrying his ass the whole tournament. When one played bad, the other one raised his game. It was like this until the Finals. Rivaldo played great against Belgium, Dinho saved Brazil's ass against England, Ronaldo was the savior against Turkey and both Rivaldo/Ronaldo played well in the Final against Germany.
Right now, Brazil is putting all the pressure on a 22 y/o boy. He needs to raise his game in all matches. When he doesn't, Brazil sucks badly.
Right now, Brazil has way more talent defensively than offensively. Brazil's main strikers are Jo and Fred. The only creative mid-fielders are William and Oscar. Compared to what Brazil had in the past, it's a joke. Hernanes, Ramires, Paulinho were defensive minded mid-fielders in Brazil that changed their style in Europe to become more offensive. But they're not creative.
Felipao uses Oscar as a defensive winger, seriously WTF. Oscar's job all game long is to cover Dani's ass and cross the ball from the right side. Not trying to defend Oscar because he is not playing well and he has been way too passive, but Felipao doesn't have a clue how to use him.
For what Oscar does right now, Brazil could simply use a player that can actually defend that knows how to dribble (Hernanes for example). Fred is simply too slow to play for this team. And he is doing a horrible job as a "pivo", holding the ball close to the area to wait for Neymar and the other players. Defenders have such an easy job covering him that it's like Brazil plays with a player less.
Brazil is struggling against high pressing teams because they have no mid-field. That's why you see David Luiz launching those long passes to the wingers all game long.
Honestly,I would change this team quite a bit. Dani and Marcelo can't play together. They're defensive liabilities and not only they put too much pressure on Luiz Gustavo, but they also ask Hulk/Oscar to run 2x more to cover them when it's necessary. Considering the options here (Maicon and Maxwell), I would take Dani out to put Maicon in. Maicon plays well on both ends and he crosses the ball very well.
Fred needs to go. Dude is horrible and he is probably the worst starting CF left in the WC.
My formation would be : (Luiz Gustavo won't be playing due to 2 yellow cards)
Defensively, 2 basic lines of 4 with Hulk/Neymar ahead. Not perfect, but fills the mid-field, take out a huge defensive hole at the right side, give more freedom to Oscar to create instead of defend (also giving him a mid-field partner to create) and Brazil's offensive game doesn't depend on using a worthless player like Fred as a "pivo" anymore. Coutinho would be great as an option right now

, but instead he chose a 5'4 mascot that doesn't even start in Ukraine.
But knowing Scolari stubbornness, I think he starts against Colombia with :
Julio Cesar
Alves - Thiago Silva - David Luiz - Marcelo
Fernandinho (replacing Gustavo's role as the main MDC) - Paulinho (he gets back because he was good 1 year ago)
Oscar (still covering Dani's ass playing as a defensive winger lol) - Neymar - Hulk
Fred (-1)
And all the problems mentioned remain the same. Unless a miracle happens, there's no way in that Brazil wins the WC with the way they have been playing and the way this team was built.
Text is a bit long, but I just wanted to share my thoughts
