1. Yes, you will be able to set patrol points for placeable NPC's in the next update (1.8). You can use the NPC Spawner (red skull icon) to connect to Waypoints as well. I'm also working on adding a zombie NPC that spits acid, a fast/sprinting zombie, and a giant zombie, to add variety.
2. You can connect waypoints to other waypoints so enemies can move as far as you'd like. You can even have them loop back. So if you have 3 waypoints, you can connect 1 to 2, 2 to 3, then 3 back to 1. This is how you make a railroad track as well.
3. Not sure I quite understand the question. I am going to redo the tutorial completely, though. For example, there is an electrical system where you can use the wrench to connect batteries, switches, motors, etc. It's really cool and hasn't really been explained yet.
Thanks again! Your feedback pushes me to get out updates more quickly :)