The emax budget escs are an oem from hobbywing, thats perfect. And the motors looks fine, too. For centerplates check this
, they have a build in power distribution.
For the flight control, you have many options, especially on integrated boards. I suggest a plain support-board where you can place an arduino and the sensors you want. With an integrated board, you should can add other sensors, but you have to carry the unused ones always with you. Check the main site to start with: http://www.multiwii.com/connecting-elements