The advanced dynamic texture has a getControlByName (or ControlsByType) function. If you provide a unique name in the editor you will be able to find them, similar to the way you are filtering the Control array. So, in you want the Title element:
const title = advancedTexture.getControlByName("Title");
Same goes to all other controls. Otherwise, you can always iterate the children like you are already doing.
Yep . Create the plane mesh, attach the GUI to the mesh, and you are good to go, including pointer events.