The sudo makes this a bit suspicious to me. Maybe you can store the results in ~/.local/share/icons/hicolor (not sure if that’s exactly the correct path. It would allow you to run this for a specific user instead of doing things with your entire system.
No worries. You have several places where you can store icons, themes, etc. The Book has some good information on this. You might not be running ArchLinux, but these paths will apply to you as well. You can basically overlap system-wide icons with user-specific icons in your home directory.
To easily get the icons from the system directory into your home directory you can just copy them and make the alterations in your home directory.
Also, like the others here also said: great work on getting so far in such a short amount of time!