I am a student and I am going to attend an academic conference in the Netherlands in early September. I have the acceptance letter for my presentation at that conference. I will also attend a conference in early December in Spain. I haven't heard back yet from my submission to the second conference. Each conference spans about 1 week, and I will be in the States for the 3 months between them.
I have my appointment of Schengen visa application at the Netherlands consulate next week. The thing is, I don't want to make separate visa applications for each of Netherlands and Spain because it costs time and money (and patience). I know that a multi-entry Schengen visa can span 180 days.
So my first question is, if I submit the itinerary and hotel reservation for both conferences at my visa application, would the Netherlands consulate give me a 3-month or 6-month multi-entry Schengen visa although I will not be traveling and will be back home in the US between them? I want to note that I will not be able to present proof of invitation from the second conference since I haven't heard back from them yet.
My second (and probably the most important) question is, is there a possibility that the Netherlands consulate will directly reject my application because I ask for a multi-entry visa covering both destinations, so I lose the chance to attend even the first conference?
And my last question is, if they give me a 3-month visa, let's say that it expires on 3rd of December, can I enter Spain on 1st or 2nd of December, or do they require longer validity of the visa after the entrance?