3. If you win Hells Week on points with Derek, you receive some kind of money that you may spend on VIP in strip club or mansion. I was always scared to take money from mansion and never met Madame Rose because of it. If you spend this money on VIP, do you get less money to spend on Halloween or where do you get less? What does it impact?
To answer this in a little more depth, the "cost" of keeping the VIP pass depends on how you are repairing the DIK mansion in Season 2.
If you have mini-games turned on, turning down the VIP pass gives you and extra
$10 to spend on the mansion repair mini-game. If you can already afford to repair every room and buy the windows before the MC and Rusty run the numbers in Episode 8, the money is of no additional use (any excess is effectively lost). It's not too hard to raise money, so in this case no particular reason to keep the VIP pass (except for roleplaying purposes, of course).
If you have mini-games turned off, however, things are a little more complicated: keeping the VIP pass *might* make the difference between Rusty keeping his car vs having to sell it for extra funding. Rusty will keep his car if a) you have 6 or more DIK reputation points, and b) EITHER you reject the VIP pass OR you volunteer to work at the old folks home at the start of Episode 7. Since the only benefit for the VIP pass so far (assuming you somehow consider Madame Rose a benefit) requires you to work at the Pink Rose, there's no particular reason to keep the pass in this scenario if you want Rusty to keep his car.
That said, if you just want to see what happens when the MC has to take the bus on his dates in Season 3, keeping the VIP pass could help with that. (Fortunately, you can still choose to ignore Madame Rose even if you visit the VIP lounge; there's just nothing else to do there at the moment.)