The 'big four' players shouldn't all be considered in the same way. Fundamentally, the days of getting either Woods or Tedesco for a bargain price are in the past: they are both established representative players with reputations, who will be able to command full market value. Perhaps either or both will offer the Tigers some sort of home-club discount, but realistically they'll cost full whack. Hopefully the club will be able to make sensible decisions about retention within a cap: there isn't a player in the game who's worth so much of your cap room that you can't surround them with a suitable supporting cast.
Brooks and to a (slightly) lesser extent Moses will still be paid to some extent for potential in all likelihood. Brooks hasn't yet lived up to expectations and while Moses has shown more he certainly hasn't demonstrated the ability to consistently deliver or to deliver when it matters most. And actually it's these two where the Tigers have an opportunity to either grab an advantage or tie themselves to another Sironen-type millstone.
There's no point waiting for Brooks to deliver before offering him a contract. If he has a great first half of 2017, guess what: the price just went up. Moses' already has. The club fundamentally has to come to its own judgement based on its own assessment of the halves talent, and try to get ahead of the competition (and market value) by locking in the players it wants to keep before their value soars. If they really believe Brooks is just coming on slowly, get him signed up as soon as possible. If they're right, great - a bargain. If they're wrong, well, sack the talent assessors and start again. But if the plan is to build from within it cannot work by waiting for players to reach their full potential and hope they show 'loyalty'.