1) Get rid of any bloatware Dell loaded on the machine, including (especially!) 3rd-party antivirus. Given Microsoft's
track record, I would *definitely* have automated backups of some sort, preferably on a separate machine. I'm a geek, so I have no inhibition about deferring Windows Updates, or disabling Windows Update entirely (albeit temporarily) whenever there's a major OS update. I prefer Firefox to Chrome, personally, due to privacy concerns and tech politics (e.g. Google's war on the address bar)
2) Windows has a built-in backup utility that's pretty reasonable to use. IIRC, if you have a NAS/file server and Win10 Pro, you can do automated backups across the network.
3) 32GB is indeed a handsome amount for just about anyone not doing heavy photo or video editing
4) Your computer sucks air in the front and out the back, so don't worry about it being on the carpet.
5) Nothing other than what Windows comes with, and staying away from shady parts of the internet.
6) If you're worried about privacy, Windows 10 isn't for you, sorry. There's Linux for that. :) * You can reduce the amount of telemetry MS gathers, but not stop it completely. And even if you do, there's a high probability the next update will restore all that functionality. One thing that can help is to *not* create a Microsoft account when first setting up the computer. It's getting trickier--MS have progressively made the "local account" option harder and harder to find--but it's still there.
* Seriously, it may be worth a try. My wife uses Windows 10 on her laptop, and I decided to give Ubuntu Mate (one flavor of Linux) a spin on my laptop, and I have to say that the experience has been far more trouble-free for me than for her. For example, Microsoft really FUBAR'd the whole printing subsystem in Windows 10 (something that was *perfectly* functional in Win7). Setting up the network printer on my Linux laptop was a piece of cake, while Windows 10 refuses to print if it senses that the printer has run out of paper (which requires you to restart the Print Spooler service), even after you've filled the printer back up.
Really, when I installed linux on my laptop, I was expecting to run into a few things that needed tweaking, but once it installed and booted to the desktop, that was it. No extra driver installs, no friction, just....ready to go.