nobody has answered his main questions yet.
30-90 Can be mostly solo'd with the exception of a few quests on kashyyyk, on Mustafar and the last legacy quest. The easiest thing you can do to start getting people to be more talkative, is talk to them first, and make sure to be nice to em. (when most people see me in eisley they dont even try to talk to me, its nice when someone does, but generally I have to make the effort) As for becoming a dark jedi, all you have to do is go into your game menu, where you find your commands, and collections, and community, and go to expertise, and then under path you can spec either Darkside, or Lightside.
As for your second gen saber, you will get the ability to craft that later on in your gameplay. Make sure you have a +15 crafting kit, some bespin port, some pyollian cake, and are using a +44.9999999 crafting station.
As for putting items in your house, all you have to do is go inside of your house, and go into your inventory, radial menu (the ~ key or the ' key by default) and hit drop. from there you can move them with various radial or text commands. /move up (or down or left or right) /rotate yaw (-180 to 180) and the new commands I wont worry about since they must be unlocked.
Hope i've been helpful