I've added Amazon links to each of those parts to confirm the specific components I recommend. Note that I linked to the M.2 version of the MX300 525GB drive, which is a lot smaller than the 2.5" version, yet costs and performs the same. You'll like the way it slots right into the motherboard. By the way, your use of the links in this thread helps support this forum, so when you're ready to order, just click on the link of the whichever part or parts you're going to order.
The one major change I would recommend, based entirely on ease of use rather than performance, is the Noctua NH-U14S CPU cooler
. It's actually a better cooler than the Thermalright Macho, but that's not the important part, given that your parents will never come close to stressing the Macho. The real benefit is that it has the best mounting mechanism in the industry, and installs in under 5 minutes. It's really, really simple. The huge size of the Macho makes it an absolute bear to install, and yet the slim NH-U14S can still outperform it do to its excellent engineering.
By the way, the I/O port cover that goes in the back of the case will come with the motherboard.