9. Horwill (starting) – is always a bit slow finding his groove after coming back from injury but will be back to his best by then.
10. Vickerman (Bench) – a big call at this stage of the year, but he is pure class and id be shocked if he is not at the WC. Is perfectly suited to come off the bench.
16. Mumm (backup/bench) – His versatility should win him a spot.
28. Horne (backup outside)
30. Davies (backup wing)
It is early, but looking at your squad I see the quoted positions as most contentious/tenuous.
It's unknown whether or not Horwill will be fit at all, let alone in form. If he is, he's a sure thing for the squad. The query for Vickerman runs along almost identical lines. The two who could benefit from this are Mumm and Douglas, with Wykes a massive dark horse. They'd probably be in that order.
At the moment, I don't think Mummy quite justifies his spot as back row/lock on form. For a versatile back rower, I'd be looking to Mowen as a 6/8.
Horney, same as the second row lads, massive question marks although noone doubts his ability. If he's not hot to trot, they might consider a crash 12. If Cooper is injured, Barnes is 10 and it can be good with his game to have a hard-running 12 outside him. At the moment, the form Aussie 12 is, go figure, Tom Carter.
I disagree with Davies being allowed anywhere near the squad. He's been seriously ordinary this year. I'd say he's behind Rooney, and Rooney's not exactly top of my totem pole at the moment. In essence, I reckon I'd use this spot to take a third hooker. Toss a coin between Charles and Fainga'a but Deans has exhibited a liking for the finger, so give it to him.