Turner backs up England's backup goalkeeper. I think he'd probably back up Pope (England's third-choice keeper) as well. Now, I think Ramsdale is better than Pickford, but I think Turner would be hard-pressed to make the England roster.
I think it's really hard to evaluate Adams against someone like Calvin Phillips. Adams is excelling in a role kind of like what Phillips excelled at with Leeds himself. Phillips isn't playing because he moved to a truly elite club. But Adams had kind of stagnated for the last season or two at Leipzig. So while I think he might be "good enough" to deserve a DM spot on England, I don't think he's shown enough that he would have been picked. And that's kind of how I feel about Pulisic as well. I think Pulisic is probably at least as good as Rashford and possibly Sterling. And could very well be as good as even Saka. But for whatever reason, he hasn't really shown it consistently. So while Sterling's form has been kind of crap this season, he has a much longer and deeper resume (for club and country) that would make most coaches, I imagine, select him over Pulisic.
Musah has one half-season of club football as a CM. He was one of the worst wingers in La Liga. I think he's great, but no way that's enough of a resume to make a club like England unless he was absolutely dominating a Top 5 league at the moment. Gio likewise just doesn't have the resume. Of all the Yanks, he's the one I'm most sure is talented enough to play for England. He might literally be talented enough to make any roster in the tournament. That's how high his ceiling is. But he hasn't put together long, consistent runs of excellent play in top-level club competitions that way Bellingham (or Pedri) or even Mason Mount (who finished in the Top 10 of the B'allon D'or a year ago have.
The case for McKennie for England would be as a set-piece threat. He's a weapon. I don't think he as good or consistent as any of England's midfielders, but he does have a unique skill-set that some coaches might value. But Ward-Prowse is probably better on set piece deliveries than Weston is as a set-piece target. And Ward-Prowse didn't make it.