You don't choose a target for Eden, Seat of the Sanctum's last ability at the time you activate it. Rather, a second "reflexive" ability triggers when you sacrifice Eden, Seat of the Sanctum this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.

Town is a land type with no special meaning. It doesn't grant the land any intrinsic abilities. Other cards may care about which lands are Towns.