A:AnswerApple is not currently part of Best Buy's student promo deals; however they are currently running a great 3-day sale on all MacBook Pros which nets you better discounts than what Apple would normally give you as students. You can also get additional money back by financing your purchase thru Best Buy and paying it off within 30 days (this would net you an additional 5-10% back in rewards depending on if you already have a card or are a new card holder).
A:AnswerAvailability on this model is going to be extremely limited because it's a custom built system. There are currently three of these. The only one with seemingly widespread availability is the MacBook Air the two Pros are going to be very much YMMV (your market may vary). Attaching custom models for your reference.
A:AnswerI would personally recommend the 15-inch MacBook Pros for CAD softwares. Versus the 13-inch models, you get a lot more processing power and they also feature dedicated graphics cards which can be extremely beneficial when working with workstation-type apps like CAD softwares and prevent you from unnecessarily taxing (or significantly consuming and slowing down) your processor and memory to render graphics. The 256GB 15-inch model will have a 2GB dedicated graphics card (GPU) and the 512GB and 1TB models both have upgraded 4GB dedicated graphic card models along with faster processors.