Yes! You can add as many section backgrounds on your page as you want. Every section can have the Parallax effect active. 

Yes! The Parallax effect includes height and width controls.

Yes! Background images are automatically device responsive. You also have responsive controls over many of the design controls for this effect.

No! No coding is required for the amazing Parallax effect. All the controls and settings are built into Elementors background Section under the Style tab.