My comments on the hookers (excluding Bhunt, because he's pretty clearly our best hooker) would be in no particular order:
Billy - Provides versatility by being able to play in the halves if injuries occur, has the best defence across the hookers... and despite not yet playing as a ball playing lock in the middle I definitely think he could. Has shown that he can play 80mins at hooker if required to do so. Often succumbs to instinctive plays and playing eyes up footy, such as kicking early for a 40/20, skillful kicks for repeat sets or running off a quick ptb (even if it's not on and no one else knows it's coming), but at times it can result in tries out of nowhere and so he has to be respected by the defence. I don't really see Billy doing much creatively with his crash runners... despite being a half and often calling his own number, I can barely recall him setting up a try off a crash runner close to the line... he's more renowned for being able to sniff out a try from running out of dummy half.
Mozer - I think he had been playing 80mins at hooker in Qcup last year, but unsure for this year. Probably has the best running game out of the hookers in the squad (Billy runs more often but too often without support and too often at the wrong times). Mozer is likely the best at engaging the defence and working with his forwards out of dummy half. Might have the best pass out of our dummy halves, but can't quite recall.... so based on all that Mozer is probably our best pure hooker. In saying this I'd say defence is the biggest question mark with Mozer, which then leads to the least amount of versatility as he can't be a ball playing tackle bot, and there's potentially an issue with his defence the longer he spends in the middle. Probably best used at this stage off the bench until he can get back up to 80mins consistently at Qcup level. May also have some question marks around his shoulder.
Paix - Can play 80mins at hooker if needed. I don't see much versatility beyond hooker though. He could probably play as a tackle bot if needed in the middle, but his defence is more catching and wrapping, unlike Billy so I think the middle would be losing the yardage game if he was playing that role. You would assume he could play as a ball playing lock if needed given his halves background, but he's been playing hooker since about U19's I believe and he seems to avoid running, so there wouldn't be much risk of a show and go, unlike Billy. I'd class him as providing more creativity than Smoothy and better at utilising his runners than Billy, but not as natural as an eyes up player like Billy is... whether that's a good thing or a bad thing.
Smoothy - Can play 80mins at hooker if needed and has been doing it for longer than the other hookers in the squad... has some skills around dummy half, but hasn't shown it at NRL level much at all. I think his pass is better than Billy and Paix. Can also play as a ball playing lock if needed so has some extra versatility and a second purpose in the 17... I'd class his defence as being better than Paix, but not as strong as cutting blokes in half like Billy. He's definitely the no frills hooker amongst the group.
So in saying all of the above, I think we've got 3 guys that are probably best suited to starting (Billy, Paix and Smoothy), but it's most likely that Bhunt will be starter when he comes back. Mozer is probably our best off the bench so he's the one I'm partnering him with Bhunt when he gets back.
I can only assume that the coaches just want to see Mozer get back up to more minutes at cup and fully heal that shoulder, so they are potentially holding him back until the back half of the year instead of having to rely on him playing 20 games or so at NRL level.