I actually posted about this several times as I had many questions (and I have seen others ask too) but for some reason Frontier has kept a lot of details pretty vague. I'll try to answer your questions to the best of my knowledge, but I don't work for Frontier so I might have this wrong.
The VIP pass is to have your name permanently placed in the game (in EVERY copy of everybodys game) as a random guest. The VIP Staff pass allows YOUR NAME to be seen as a random employee in all players parks around the world. These are only available for a limited time, for having your name appear as a random guest or employee. Its just a nice way of giving Frontier a little tip for saying "thanks on making such a great game" and them saying your welcome [money]
If you do not purchase the VIP pass, then you will not have your name visible as a random guest or staff in everybodys parks. But there will still be a Guest Creator for you to utilize and add your own characters into YOUR personal game. At least, that is what I have been told by Joel [heart] The VIP creator is a limited time thing for your name to be entered into ALL copies of the game for ever, and this will not be available for purchase after the game is released. The standard Guest Creator will always be available (and its most likely included free with the game) but I wouldnt expect a staff creator
Like I said, this is all very confusing and vague IMO and a lot of the details are not confirmed. Most people are just assuming these things. I'm hoping for multiplayer/co-op to visit other players parks, and hopefully we will be able to see our created Guest when we play online or when other people visit our parks. But that is not confirmed yet, and I wonder how many people are confused by this? I wish Frontier wasn't being secretive on a lot of details (like multiplayer) because it would only help increase sales if they were more clear on things. One thing that we know is confirmed, First Person mode is in the works and will hopefully be revealed in full detail soon!! Expect more news on Alpha 3 coming in a few weeks!!!