Could run it like this no problem, but I think I would like to experiment with GPT.
Really no difference as far as running goes than MBR, you simply get more Primaries, plus the boot file (the same as MBR are stored in more than one place on the drive. Not just that hidden area where one has to use a partition tool to reset MBR after a wipe, to prevent getting the 'grub rescue' error if Linux has been installed & the proper key to boot from USB isn't hit fast enough. It's stored in more than one place on GPT partitioned drives for safety, although like any other, deleted when wiped, still have to get that hidden area.
The other thing being, if you add a second drive for storage only & it's under 2TB, while you can initialize & create partitions with GPT as desired, WD & other OEM's recommends to use MBR instead. Should you need to swap a MBR (non-boot) drive to GPT, you can do so w/out losing data, or vise versa. I've done this several times & have lost nothing. What I don't know is why the same can't be done with a bootable drive, there may be a workaround, yet haven't ran across any, if so, could had saved you a lot of work.
Nothing there to experiment with, unless you want to create 50+ partitions for the sake of it. What you do get is the convenience of having as many of these as you need, depending on drive space & making Logical partitioning a thing of yesteryear on any computer that ships with Windows 8 or newer, to include many late W7 models. Another thing about the HP you own, the MB is manufactured by Gigabyte (had to read the specs twice to make sure there were no MB swap! ), so likely better than many of HP's offerings. Since I don't get many (newer) HP's coming my way, is the first time I've seen this, hopefully won't be the last, and not the 'bottom of the barrel' of Gigabyte's offerings. I'd be interested in seeing the overall build quality & features compared to their retail MB's.
1. What about Imaging with GPT, I thought this was harder, or something I remember reading to that effect. I have imaged my Windows 8 machine, but now thinking about it, need to go back and see what actually was backed up. I used AOMEI, and tried normal backup and System OS Only Backup also, as far as I can remember.
No difference at all, drive images works the same way, and no more space required on the external. Although if needed, you will have to create the bootable rescue media just like the OS stick, with Rufus using the same mode. Or if the DVD/CD RW is there, can use that, just slower to load. This is what I like about Macrium Reflect, under 'Other Options', there the choice to create a boot option direct to Macrium to make backup/restore easy. Backups are far less likely to be corrupted running like this & because Windows isn't running, faster also. Restores are just as easy, as long as the menu is bootable, any Linux install won't wipe this out.
I'l also considering using Two Drives, one for Ten, and another for Linux, but that will take more resources, and perhaps create more heat in a machine that is already creating more heat than my previous Dell 660s.
A second drive won't use that much more resources within itself, I have a couple with 4 drives (one a Dell OEM machine). Although you may want to inspect inside of the case very well, there could be a semi hidden place for a intake fan, which many OEM models doesn't ship with. On my XPS 8700, had to run a PWM splitter to control both fans & then use SpeedFan to make these run faster. Was running at 808 rpm steady, now at a predefined curve, all the way to 3,000 rpm if needed & not much louder because I installed silicone washers between fans & case. These are 92mm fans on the Dell. The faster these can be made to run, the more heat that can be pumped out. Same applies to CPU fan. If interested, you can always create a new Topic to discuss this further.
As noted in the link to the manual you provided, external/internal cleaning is recommended on a regular basis. That action alone reduces heat buildup to a larger degree than many thinks, the lack of doing so are likely the #1 killer of any computer.
Keeping your computer system free of dust, dirt, and heat will prolong its life. Dust, pet hair, and other particles can build up, creating a blanket effect; as a result, components can overheat, or, in the case of the keyboard and mouse, not work smoothly and effectively. Check your system once a month for visible signs of dust and debris, and clean it about once every three months
Good Luck with your new HP, I believe you'll be just fine with & enjoy it!