We've three academy midfielders in the first team squad. Lyon we know plays as an attacking mid and I very much doubt he's got the muscle to play elsewhere in the central positions. Stanway I feel would be too reckless in the tackle to hold down the defensive midfield slot. I see him more as a box to box mid.
I don't know Zander's preferred midfield position but he's clearly not the answer as a back up fullback. Possibly would be OK coming on as a wingback if we went to a back three, but that's a different matter. So yes, perhaps he could slot into McBeth's role and allow Luke to drop back. Even if McBeth stays in midfield we could do with a back up defensive mid. Agree, he's certainly got the strength for the job.
Another way of looking at things is to wonder where and when MacKenzie is likely to feature. I'd say Wasiri, Muirhead & O'Reilly are ahead of him as back up fullbacks. Both Stanway & Lyon more likely to come on as midfield subs. So unless Zander can fill in as a defensive mid then he's not due much game time.
Personally I think, regardless of his best position and with four other centrebacks in the squad, Luke is destined to play midfield (near future anyway). It does still raise the question who'll play defensive mid if he's unavailable. Zander's as good, if not better, a shout than any other midfielder.