I'd rather have Henderson, Milner and Coutinho than the 3 you mentioned for Everton. Clev is very average and Barkley is overrated in terms of his current level. Lukaku is good but both sturridge and Benteke are better strikers in my book. The Everton back 5 is better though, I agree.
I do agree the squad isn't as good as it should be considering the money spent, I said so in my earlier post blaming Rodgers for some poor signings but I believe he isn't even getting the best out of what he has which is worse.
Neither Henderson or Milner are even competent at playing as a DM. Lucas is but he is average contrary to what Liverpool fans may think . Coutinho Henderson and Milner is a midfield that won't provide any support to the defence and will concede. Plus Milner isn't a very good creative mid to offset that with attacking prowess. And coutinho is a 10. He isn't a 8. He can play in midfield if he has a matic and a Herrera kind of players alongside him. Milner or Henderson maybe like Herrera but they have no one even close to matic. Barry and McCarthy can do that well enough for Everton and thus Barkley or clev can play in midfield freely