They recommend W7 or W8/8.1. As of the listing for 2016 W10 is not on the recommended OS list. I would think they're going to wait a bit to see how W10 pans out before making a version that supports it.
According to what I've read you don't need a hotrod system to run AutoCAD. On their website they state that AutoCAD will run on a Pentium4. Having said that I would build for worst case scenario. I'd go with at least an i5 and 16gigs of ram.
Using an SSD will make it go faster somewhat but keep in mind an SSD's life span is much shorter than a mechanical drive. The read/write cycles are limited. High end SSD's will last longer but not by much.
But you do need a higher end video card. Some software and mainframe systems use the GPU to do all the heavy lifting as far as rendering for 3D simulations. Cray super computers use Nvidia and AMD graphics cards as the heart of the system.
IMO a desktop system will serve you a lot better than a laptop because of the amount of heat that is generated by components when they are working. Even though AutoCAD will run on a laptop a desk system will allow you to fine tune the cooling devices to suite the amount of heat it needs to get rid of.
It's up to you. Give this a look: System requirements for AutoCAD | AutoCAD | Autodesk Knowledge Network