There's no specifics here. To take things one at a time and assuming you are buying your pheasants in as poults at around 7 weeks old:
1. Anything up to 6 tons of wheat per 1,000 pheasants! Depends on how quickly they are shot, how soon you put them on wheat from pellets, what other critters take advantage, what natural food is about, how many pheasants are predated or wander off never to return, even the weather has an effect on their appetite. Try to save on wheat and in the long run, some of the birds will desert you. Also provide as many feeders as feasible, a cock bird will try to monopolise a feeder for himself and his hareem. It's not realistic to provide feeders for all, but more rather than less.
2. Ground rent is such a difficult one to call. You might be lucky to pay nothing apart from a free gun to the owner and vermin control services. But it goes up on a sliding scale from there. Depends on the landowner, the type of land, what percentages of woods there are and probably many other factors.
3. Bag sizes? Another one that's hard to call due to all sorts of reasons. Let's say, for argument's sake you manage to shoot a third of the birds put down. So that's 1,150-ish. Let's also say you have 10 shoot days (because the maths is easier). You could look forward to shooting around 115 birds per day. But again, that will have so many variations. On a new shoot, that could be less until you get the lie of the land and know where they'll fly, some shoot days will produce more, some less, how well you've husbanded/dogged in your birds, how good the guns are, the topography, the weather. So many variables!
I think you need a season to be able to sort out most of those imponderables. Come February, you'll have a good idea and will likely do much better in year 2. As for paying guns and what to charge, assuming it's a friendly syndicate, it's not unreasonable to work out a cost for poults/feed assuming a minimal amount of wheat, with a proviso that, say in December you'll have a much better idea of how much you'll need buy for the rest of the season and can say to them that there may/may not be a surcharge then to take you through. That way, they'll feel they aren't being over-charged.