I will make only a brief comment before I post my thoughts on the situation. That is, I wasn't at the event, nor do I know anything about the judges in Barcelona. I will not make any comment on how they handled it, speculate as to what did or did not happen, nor pass judgement on their decision. While I may not come to the same decision that the judge did in your situations, that does not mean they made the wrong decision. Both of the situations you present are sufficiently complicated that there are several avenues to approach, and there is no outright wrong one. My answers are simply my own, and are not to mean anything beyond that.
Anyhow, on to the situations.
Situation 1: There are a couple of problems here. Firstly, while this could indeed be "Improper Draw at Start of Game", the game has also actually started. So, this penalty isn't really necessary appropriate at this point as we've already begun a game, both players had made plays, and they are past the point where we really could correct this problem in this way. Secondly, there's the question of how much impact that the lack of a card had on Player 1s first turn, as well as Player 2s second turn (since whatever the 7th card may have been might have been playable and affected Player 2). Thirdly, there's the question of how to fix the situation, or if it is even fixable.
I would immediately rule out either going back to an earlier point in the turn, or going back to a prior turn entirely. Neither of those is a very good solution at all. It's one thing to reverse a play, it's quite another to go back that far. I would also immediately rule out allowing Player 1 to draw a card for his 7th to bring him to the right number. Player 1 definitely did something inappropriate here, and the game state shouldn't (and wouldn't in reality) just be "fixed" by giving Player 1 his 7th card.
So, the only real two options here would be to 1.) give Player 1 a Warning at this point for a Procedural Error - Major (because of the game actions that have occured after when the "real penalty" occured) or 2.) give Player 1 a Game Loss for a Procedural Error - Severe. If the game could progress from this point on, which it looks like it can, I would leave the game as is and let it finish out at this point (Player 1 gets a Warning). If not, then it has to be a Game Loss. But, in this situation, it looks like the game can continue on from this point.
Situation 2: Both players are clearly at fault. Player 1 for not paying enough mana for the Impulse, and Player 2 for not reminding Player 1 that he had to pay


instead of


. Secondly, there is the problem with whether or not Player 1 mixed up the cards in his Hand with the cards from his Library. Which makes it even more severe and not just looking at extra cards or drawing extra cards, as it could be abused. So, I would probably have to walk through the entire situation and confirm a fair amount of information as to what happened regarding the Hand and Library. But, what is likely to happen is that Player 1 will receive a Game Loss due to the compounded nature of the problem and Player 2 will receive a Warning as well.
But, I may take a long look at what happened here, as Player 2 could have been gunning for Player 1 receiving a Game Loss (for example, did Player 1 immediately resolve the Impulse because Player 2 had no open mana or cards in hand; or did Player 1 wait for Player 2 to respond and then resolved the Impulse after Player 2 said "Okay").