Outlets cannot be guaranteed, though your chances are very good; Their avalibility depends on whether and when the car has been refurbished, and not all coaches have been. There is no business class service on the Florida trains - just coach and first-class (sleeper), with sleeper being really the only way to absolutely, positively guarantee personal use of an outlet. Even if you happen to end up in a car without outlets, though, you can still generally use the outlets in the lounge to recharge devices.
There is no wifi or other internet access yet available. It's coming, but don't hold your breath...
Kissimmee is somewhat closer to WDW destinations than Orlando, but you stop in Orlando first (southbound), and it is the larger station.