Yes, there is a simple GUI where you can select several different variables within the client itself. Including max block size generated, max accepted blocksize and block depth. It is able of tracking a fork and once it reaches a particular block depth it can switch over. This all depends on the settings that the user chooses. By default Bitcoin Unlimited will behave exactly like Core until the majority of the hashpower starts to mine larger blocks.
Interesting. What is preventing entities from cheating the system by running thousands of clients with bogus votes?
It is the miners that create new blocks, that is what counts, nodes simply choose whether to follow the miners or not. Nodes can be spoofed, proof of work can not, this is why it works.
Essentially Bitcoin Unlimited is just giving people the freedom of choice, instead of this choice being made by any development team.
This is false. People make their choice once they decide to run Core (that's their choice; they could run other implementations).
Having several viable options between multiple implementations, does enable people to have the freedom of choice, which is similar to a representative democracy. However Bitcoin Unlimited is different in regards to the blocksize, it can be more accurately described as a more direct form of democracy, which I would argue is superior.