A. Although 360 doesn't have a fiber optic port, it can still use FiOs internet via ethernet or wireless. Yes, wireless will go through the walls too.
B. All Xbox 360s have the ability to make Silver accounts. Gold costs money per month and when you buy the Xbox 360 they give you a month of gold free.
Gold lets you get demos earlier and play online multiplayer, but silver can still play on the same system multiplayer.