Those two statement are kind contradictory IMHO
Busquets: starting DM
Iniesta,Paulinho,Alena are back up CM, Denis and Roberto are possible back up for that position too.
That is 6 midfielders already, this limit our ability to sign new midfielders, that is why you see a guy like Ceballos would go to RM, we already have a crowded midfield even if it is with lower quality and he sees them as a club that was succesful with young players.
You can convince a star player like Coutinho who knows that he will walk into our starting line up, but it will be tough to sign two of those. Groetzke/Seri etc will be tough to convince with such crowded midfield, we will need to sell more than Gomes/Rakitic to get them.
Denis is not a midfielder for me. He is an option for the wings, or a candidate to be sold for some good price. Don't like him in a midfield 3. So that leaves for me Paulinho, Busquets and Roberto. Rakitic and Gomes sold for good money and Iniesta should play only from time to time and the easier games, with maybe minutes in the big ones like Xavi in 14-15, where he can impact the game for a limited time.
From Paulinho, Busi, and Roberto only 1 should be a starter and that's Busi, while the other 2 can be squad player who play or don't play depending on the game and the opponent.
This means we need direct Iniesta replacement, maybe Coutinho, if not possibly Lemar or some other player. And we also need Rakitic replacement, only simply better on the ball and with better passing skills. That can be Seri, or even Goretzka.
We need to sell Rakitic, Gomes, Rafinha, Arda, Vidal, Alcacer, Denis. Bring in Coutinho, Seri, Goretzka if possible, promote Alena. 7 out, only 3 in but top quality. Alena as the 4th.
All 3 players can be signed.