fluctuations are the same

Your bankroll would fluctuate to the same degree. The second player has the exact same 10% chance, even if it is known that there is nothing under his cup. The variance is a function of the payout structure. Information that cannot be used can't possible have any affect on the variance.

Suppose you are playing heads up and have a 3% edge on the next hand of blackjack. Would your edge, or your standard deviation, change if someone else took a peek at the next few cards before they were dealt but did not give you any hint?

There are a few things that are throwing you off. I like adhoc's example of drawing cards from the middle of the table. Think about that some more if my the example I'm about to give doesn't allow you to see the light.

Let's revisit an example I gave before and we'll go very slowly:

We have five players. Before the deal, you have 52 cards remaining in the shoe. You have a true count of +4. So you have 4 more high cards than low ones in the pool of cards to be dealt. You and third base make your bets. They deal your card face down. Now the next three players get their cards face up. All three are tens or aces. Now third base gets his face down.

Now, you may think that you had better chances because you got dealt your first card while these three high cards were still in the deck and the true count was higher than it was when 3rd base got dealt his. You are thinking that you drew your card from a 52 card pool that was 4 high cards rich. Now third base is drawing from a 49 card pool that is one high card rich. But this is an illusion. The three cards that were dealt to the players between first and third were never really in the pool of cards available to you. You just thought they were. In truth, they were designated for these other players and you couldn't get them. So you were also drawing your card from a pool of 49 cards that was 1 high card rich, not a 52 card pool 4 high cards rich.

You can see that 1st base's faulty true count estimate, the best estimate you could make based on what he had seen so far, is off by exactly the same margin for both first and third base. So it is not only the edge that is the same. There margin of error, the variance of their true count estimate, is also exactly the same.

If, before betting, 1st base was allowed to see the three cards that would be dealt to the players between himself and third base then he would asses the true count as something close to +1 and bet accordingly.

The advantage and variance are the same for both players. If strategy variations are not being employed then the chances are entirely equal in every way.