2. In practical use, mining pools are accumulating amounts in the "payout wallet" and redistribute rewards (which can be optional). CatchThatRabbit pool has the following payout address: https://blockindex.net/address/cb6225ef1958b654995bd5bdf10e874c903e8a139669
Accumulating coins from rewards to pay to the miners. ⬇️
4. The formula to calculate the reward is as follows (in most PoW pools):
Your reward = 5 XCB × (1 - pool fee) × (your scoring hashrate / pool scoring hashrate)
Decentralization is on all levels - even in the pools themselves.