In the interest of actually getting this done, I will try and keep this as brief as I can. I might, however, elaborate at a later stage.
After much waiting the day had finally come, when the parcel collection card for my screen showed up in my mailbox, meaning I could finally start the build. I picked it up from the post office straight away, and un-boxed it on my lunch break at work.
I also tried out some ideas for possible internal component layouts, using the provided cables. In doing so, I found that I had to have the HID USB cable sticking out of the case in order to have the rest of the RPi’s ports be accessible from the outside. While this was inconvenient, there was not much I could do about this without doing some heavy modifications to the ports, which I was not ready to do. So I would have to live with that slight issue for the time being.