2. Why there is a miner to download, when it is 100% PoS?
3. Is buying 1000 XEL the only way to earn more coins?
4. Where is the elastic computer in all that?
I am a bit surprised that you are asking these kind of questions. Obviously, you have neither read the whitepaper nor did you take even a quick look at the website. The information you are looking for is all there!