Not sure if I'm answering your question, but regarding point a - the cost of purchases is accounted for in the balance sheet (fixed assets) and as
@The Esk stated in an earlier post, the only effect of purchases is the amortisation of the players contract. The increase in revenue is reflected in the profit made on a player (basically a profit on disposal brought into the player trading account in the statutory accounts), but a loss on disposal of a player is discounted for STCC if my reading of esk's post is correct. Haven't checked to be honest.
Point b - no expenditure on players with regards to the acquisition of the contract is reflected in the P&L, just the amortization figure in the player trading account.
If I've misunderstood your questions, I apologise but that puts the player dealings into the context of statutory accounts and STCC hopefully.