I actually think you can do most if not all of the things I did with weapons with the item maker :) I can give you some idea of how I'd do it:
3. I actually used a slash-type weapon with a duration for the railgun. You can adjust the arc length + "duration" to achieve this affect. Then you use weapon effects to spawn projectiles out the end.
4. You can make a magic wand-type effect by using a multiweapon, and using multiple different items that each have their own weapon effects. Set the order to "randomized", and it'll cause a different effect each time.