Sure you can do it !
The whole interface is just a lot of blueprints and widgets, A lot of buttons, images and imageswitchers !
before start making stuff know that you can “nest thing” for example, you can create a widget called “Char_info” that show an image, and some buttons for attacks and life with variables.
Then in another widget you can drop in ,4 of your “Char_info” and define the exact image and values.
The viewport , is a bit tricky i am not sure the best option but i remember i used one time a target render to sent what the camera view, to a “render target” in the widget.
maybe was a material i really dont remember but doing so, you will end up with an image that you can place anywhere with any size.
So the Camera1 is the one you add all the widget and buttons and a special widget with a render-target of the Camera2