Is the download from that point on "pausible" in the sense that I could download for the day, shut my Internet down for the night and pick up where I left off in the morning, similar to how Steam download's work?
Yes. Unfortunately the game itself, all updates as well as any marketplace addons (including the free ones) are downloaded through the game's own downloader (missing out on Steam's ludicrous download speeds). However, if you need to stop before completion (or force-restart the download - sometimes it hangs), it will restart from where you left.
Btw, since you have a nvidia gpu, so far as graphics settings are concerned, I suggest you use the Geforce Experience tool to set your initial settings and tweak from there (or just leave them be). The graphics settings available are quite a lot, and it's not always easy to know which are the ones that cost more fps, and which are the ones you can push a little further.
So... that loading screen takes an awful long time. I only need to learn about new things after an update. Any way to disable it so that I go straight to the main menu? I didn't see any choices in the option screen.
I don't think there is, no. I think the introvideos can be disabled, but the loading time is pretty much the same. If you find out there is a way to make loading faster (besides using a SSD), let us know!
Good luck, and welcome to our little merry band of couch aviators
