I'd assume, given Luiz is gone and Kamara is still going to be missing for a while, we'd be keeping Enzo around. We can put Onana and Tielemans into the starting 11 instead if Kamara and Luiz, and that leaves us with Barkley as the only alternative option. I know we've got McGinn, Bailey, Rogers, Ramsey, and Philogene to work with too, but they all seem like more attacking players than Enzo.
I can see a world where Barranechea gets a few minutes this season here and there while Onana and Kamara trade games during busy weeks. Then we cash in big on Kamara next summer for PSR, and Barranechea steps up into the rotation with a years experience working with Emery under his belt. Obviously it could go wildly wrong, but I like the idea that most of our signings seem to have an eye on the future.
I think there is a reasonable chance that (in broad terms) Tielemans is Luiz replacement, and Onana is Karama. (no like for like as such - but I think thats the pivot Unai will be playing next season).
Probably sensible for the future to get him plenty more game time. Probably not sensible for our squad depth this season.