Downloaded ISO, created a bootable USB drive with Bootcamp Assistant, (SOLVED)

Background: I'm a broke artist building my own PC to facilitate better video editing and creative streaming on twitch, and I'm pretty new at this, but I've been doing a lot of research and I think (I hope) I'm starting to get it. This technology is a huge and complicated and rapidly changing world, as far as I can tell. I've gained a major appreciation of this site and several others in my hunt for inexpensive solutions to my problems--thanks for being here! I'm a lurker by habit and generally afraid of saying anything... I apologize in advance for the reiteration of questions I know you've answered a million times. I'm trying to double-triple-check.

Steps so far:
1. I downloaded the Windows 10 64-bit ISO from the Media Creation page on the Microsoft website (I made an account just for this post, so I can't post links) (I think it's the Home version as opposed to Pro or Enterprise. I don't mind too much as I haven't bothered to learn the differences. I don't think it'll matter for my purposes—let me know if you think I should look into this further—for example, should I try something like the download found at HeiDoc.net, to which a "Windows 10, The Ultimate Repository" post on MDL links instead?)

2. I used my macbook's Bootcamp Assistant to create a bootable USB drive from the ISO. I was a little concerned about there being some weird compatibility software possibly downloaded automatically by Mac, but all the other bootable-USB-drive-creators seemed to work only with Windows/Linux, and my google searching seemed to indicate that this was the simplest way to use my Mac to make a bootable USB drive.

The last of my PC components are arriving Friday (Tomorrow!!!! Like Christmas morning), so after I put it all together, Motherboard and Ram and CPU and CPU cooler and GPU and PSU and SSD and HDD and Optical Drive and Card Reader etc.... I think I'm supposed to

3. boot my newly functioning PC from the USB drive, install Windows 10, and then

4. To activate Windows 10, if I understand correctly, during the install process I'll answer "not now" when it asks for a product key, I'll turn off Windows Defender, then I'll install and run the Microsoft Toolkit I can get from the lovely MDL forums. Should I put the Microsoft Toolkit on another USB drive or download it over LAN on the new computer, or does it not matter?
Is the MDL forum post with a download link for the Microsoft Toolkit... 2.6.2 currently, I believe, the one I'm looking for? I can't link to it, but it's originally from this post:
Microsoft Toolkit - Official KMS Solution for Microsoft Products
Discussion in 'KMS tools' started by CODYQX4, Aug 16, 2011.

Final question:
-Will I need to worry about Microsoft discovering my dirty little piracy secret and kicking me off of their software, or is the Microsoft Toolkit pretty much foolproof? I've looked around for the place where I can buy just a licensing key, since I already created my own bootable USB drive, and I can't find a place for that--it's all with a box or a USB drive and I feel like it shouldn't be so expensive for just the activation. Do you know of a place to buy just the activation key? I haven't done anything illegal yet and if I can save up and pay a little bit for the peace of mind, the certainty that they won't come yell at me about stealing, I'll do that. I may have inadvertently made this more difficult for myself than it needed to be.

Thanks so much for your generosity! I appreciate your savvy.

Edit: I did some more googling about activation keys. Can I buy a cheap activation key for Windows 7 on ebay (they go for like $5!) and use it for Windows 10? It seems like that might be possible from what I'm reading...

TLDR; building PC, need to install Windows 10. Will the Microsoft Toolkit here work to activate it?

 

Thanks for your help!