I'm quite unfamiliar with Google sheets, could any of you answer the following questions:
Is hiding/unhiding individual sheets supported?
Is locked/unlocked cells supported?
Is password protecting individual sheets supported?

BTW, I need hiding/unhiding for not displaying things that you don't need to see, but are needed for things to work.
Need locked/unlocked cells for better usability.
Password protection for locked/unlocked cells to work and limitat editing by people.

Thanks in advance.

Its been awhile since I used google sheets.

I don't think there is a way to hide 1 sheet from another if its in the same file.

For privacy reasons you can have it "invite by link only" but I think it gives access to the whole sheet document.

Perhaps check out the Google help forums. They would be of better help.
https://productforums.google.com/forum/#!forum/docs

Thanks for the link. Short answer is yes to all :)