1. yes, the nebula must be destroyed before you can create the star.
2. I don't think so.
3. I don't know.
Welcome to the game! you should try some of the mods, too. I like CB a lot, and I hear the Adamant is good, although I've never tried it. Proportions makes for a long game, but it has a following, as well. I haven't given the Skywalker mod a try yet, either, but it sounds promising. I know there are some I'm forgetting to mention.
OH! TDM. it's an AI only mod, keeping the stock tech files. You should prolly start there in your journey of exploration.
