"For the good of the people" means "in the best interests of the citizens". It's an important distinction that the line does not mean that the government should always make the most popular decision. It's saying that the government should always consider what will most benefit the people that they represent or rule.
The second line (follow in everything the general will) does suggest that the government should make the popular choice.
As a whole and without further context, the author is suggesting (wrongly, in my opinion) that the best interests of the people are served by always making the most popular choice.
"Will" in this context means that which the people want and desire. So the government should do what the people want.
It is every parent's "will" that their child be healthy. As children, it is our "will" that our parents always treat us fairly.
EDIT: I addressed the quotes you listed, please do not assume that the answers address the essay in its entirety.
Actually, I think good-old "free" is the best choice, as in:
having no obligations (as to work) or commitments;
not taken up with commitments or obligations;
not obstructed, restricted, or impeded;
but especially:
not being used or occupied.
I'm not sure what you mean by "They are about to help others in other activities", but I presume you mean that, in a work situation, they have finished their task but are still at work (and expected to be working). In this case, you would not call this "free time", as they are not completely at their leisure. "free time" is usually reserved for non-restriction, such as outside of work, or during work when there is absolutely no work to do and no one to help.
Referring to the person as "free" is still appropriate, mostly in the sense of the last definition: they are "not being used or occupied". It is common to ask someone in the workplace "Are you free?" meaning are you not busy so that you can help/do something?
"idle" would suggest that the person is not doing anything useful. Assuming they are about to help others, they are not really idle, but they are free to help others.
"available" is also perfectly appropriate; "are you available?" is in fact a more formal way to ask "Are you free?"
Best Answer
Depending on the context the person or group can have different names:
Followee [followees - plural] - A person who is being tracked on a social media website or application; A person who is being followed.
Leader - The person who leads or commands a group, organization, or country; One who guides others in action or opinion; one who takes the lead in any business, enterprise, or movement; one who is ‘followed’.
Guide - A person who shows the way to others, especially one employed to show tourists around places of interest.
This person can also be a commanding officer (CO) in the context of missions, a conductor, maybe a profile or an account.