Should a republic be made up of small group of like-minded people? or, is diversity of opinion beneficial to the success of a federal government?

Both! I would think more so different minded people, because if we all think the same, we would all miss good and creative ideas to improve. But with different people, you also run into the issue of disagreeing. I hope this helps!

Yes, to have a very diverse group of policy makers is beneficial for any government and institution to run its system.The people from the diverse background have a very diverse mentality which helps in covering all the communities inside the state. As the policies made are then beneficial for every person in the community.

"In a democratic form of system the political parties elect there representatives to take part in the elections arranged by the state to make policies for the sake of state welfare."

As the public do the voting and select the representatives to acquire power to run the government and state.

In a system of governance in which a single person is in power or a group of people holds more power as compared to other officials or personnel in the system.

As a the person who is the head of state is not gone through the process of elections but it over takes the government in power and takes power from it.Mostly dictators are military leaders.

Explanation:

Now, the best way or the system which is favorable to run a state is that there should be adversity among the people who make the policies. As the parties or people making the policies will look into the public interests with abroad minded view. Along with that in a state there are always people with different ethnicity and backgrounds but when they there are people with equal mental background and level there will be no power and diversity among the policies to be, which gives an upper hand to the government in power to satisfy all the communities inside a state.