Methods for the fabrication of a Microelectromechanical Systems (“MEMS”) devices are provided, as are MEMS devices. In one embodiment, the MEMS device fabrication method includes forming at least one via opening extending into a substrate wafer, depositing a body of electrically-conductive material over the substrate wafer and into the via opening to produce a via, bonding the substrate wafer to a transducer wafer having an electrically-conductive transducer layer, and forming an electrical connection between the via and the electrically-conductive transducer layer. The substrate wafer is thinned to reveal the via through a bottom surface of the substrate wafer, and a backside conductor is produced over a bottom surface of the substrate wafer electrically coupled to the via.