Another thing not included in the profit chart is investor activity.
I tend to make a simplified example to show how this can influence your profits:

At a 100BTC bankroll, you have 1BTC invested. A player wins 10BTC, leaving you with 0.9BTC invested.
Now a new investor joins and invests 110BTC, bringing the total bankroll to 200BTC. The player from before loses 15BTC this time.
Your investment will now be at 0.9675BTC (profit: -0.0325), while the casinos profit is 5BTC.

As you can see, other investors can influence your profits and make them negative, while the casino as a whole (globally) still has positive numbers (and shows these in the chart).

No.

It affects the first withdrawal from a new account, especially when that account has no deposits.

Quoting the ToS on that matter:
"6. Withdrawal:
6.4. In some cases, the first withdrawal on an users account has to be manually confirmed. The site reserves the right to do this and as a result, those withdrawals can take up to a couple of hours."

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That's more likely related to depositing highrollers winning bets like this one (1.36BTC profit).
Attempted faucet abuse was a problem in the past, but there are several rules in place trying to prevent it and catch abusers.