I was reading some information about staying in the Netherlands on ind.nl and am wondering if they really ask for all the things listed. I will be staying with a friend for 2 months. What will I most likely need to show? Is proof of funds, travel insurance, employer's declaration really necessary?... I will have the return ticket. At worst, will my friend have to sponsor my stay since I won't have a hotel booking to show?

Sorry for the questions, but I'm quite stressed about this, as I won't be working during that period of traveling and studying full time online. I feel like they may be suspicious of a 2 month stay. Or is this quite a common thing?

By the way, I am from the US.