**HWID activation is not working because of server-side changes at Microsoft. Use the KMS38 option for now. Your previously established HWID is safe. This happened because of [recent change](https://devicepartner.microsoft.com/en-us/communications/comm-windows-ends-installation-path-for-free-windows-7-8-upgrade) to not allow Windows 7/8 free upgrades.
You can not remove it, same as you can not remove official Windows digital (HWID) license. Once a system is activated, this activation cannot be removed because the license is stored in the Microsoft servers and not in the user's system. MS checks the hardware ID (HWID) and if a license is found in their database, the system will automatically activate.
MAS is fully [open source](index.html#MAS_Latest_Release). You can open the batch files with notepad and verify it. It has many users/stars on Github. You can even perform the activation manually, check Doc section for instructions.
Yes, use Ohook activation option. However, you can't get server-side O365 specific features such as 1TB storage in Onedrive, though almost all other features and 5GB storage in free onedrive account would work fine.
It's because it's a community project and involves many contributors, splitting donations is not practical and also because profiting from piracy is not good.