I understand what you're saying and I agree 100% that our achilles heel was the defense last season. So we've brought in a top CB and a top RB (and we have some great young CBs coming through). We also had problems defensively because the people in front of them didn't help them enough. Ndidi is only getting better and I still believe that Iborra, Silva and Choudhury have the class to help our defence. In fact I like the midfield. Mahrez leaving is a plus defensively and he's being replaced as an attacking threat by Maddison.
I think playing 2 "wingers" is not the way forward - they don't help defensively so the move to attacking wing backs could mean we push at least one of those midfielders into a more central role, stiffening the team. I know you don't think Gray, Albrighton and Diabaté are up to it but Albrighton always puts the effort in and so bolsters us defensively and Gray and Diabaté are young and sure to improve - Gray is already an England U21 international and Diabaté looked tricky going forward in his first taste of British let alone Prem football. We also have other youngsters on the edge of breaking through.
I really don't see how we can need 3 players for the first 11. one maybe.
Of course we can support the wages but it would make sense to offload the high earners who are not getting playing time, so Musa, ulloa, King, possibly Slim can go.
Only Morgan of the players that you've mentioned was a starter last season. We've already brought in Evans to replace him - Evans is a top Prem CB. Gray wasn't a starter and I think we've brought Maddison in to replace the departed Mahrez. King and James were not even with the team, let alone on the bench most of the season. they are perhaps 7th and 8th or ower on the midfield list.
So I'm still not sure which 3 players in our potential starting eleven at this moment you would replace.