Yes, only Holgate and Digne can play anything other than a deeper sitting defence.
I highlighted Branthwaite as someone who may also be able to cope with a high line (note 'may') but weve not seen enough of him yet. Also possibly Nkounkou so perhaps both the left backs.
As i initially highlighted, ideally we would need a new rapid RB then we may be able to have Mina there alongside Holgate as we would have 3 players with pace. Though as i wrote, Tomori would be a decent shout because hes rapid and could easily play a high line.
Furnishing Keane with a new contract seems to be a sign that we will be going very defensive and deep though.
So looks like Allan / Doucoure then add in the yards in midfield allowing us to be hard to break down.
Concern would be how we actually get up the pitch lol