I am surprised no one has asked this question yet but,
How the hell are you going to maintain a power supply for your 4 compiters? McDonalds isnt exactly known for their availability of outlets.
How old are you guys anyway. If you are like just a bunch of middle schoolers/14 year olds I do expect you to get kicked out of there pretty fast, because people especially don't tolerate unsupervised screaming children playing video games in a restuarant.
Also if you are staying in there for 4+ hours I think you should consider the fact that McDonalds is universally known for having an abundance of flies inside the restuarant as well as filthy seats that are sticky and unsanitary due to spilled food and ketchup smears. That to me is kind of like sitting in a barn full of animals.