• the right hand column is value of the SE holdings
• Steem savings is the money made from leasing. It's a coincidence that's its the exact same as BTC holdings
• Yes, the unleased balance changes as tokens are issued and lease's are cancelled
• Add up weekly earnings from everything and times it by 4, there's no special formula

The forecast earning are based on the 1st month's earnings, they are pretty much the same. If we were to stay at 10,000 tokens issued, this is what we should earn. I calculate them by adding on the incomes together.