So here is what I got to work for mine. I’m not sure if this applies to your situation or not.
I created the regular UMG for our Main Menu and set up all of the functions that controlled the button presses and other options that the player can select in the UMG. I then created a second UMG and instead of using the drop down for the parent class, I deleted the Root Panel and then dragged the original UMG for the Main Menu onto the canvas from the “user created widgets” section on the left hand side in the designer palette. I was then able to access all of the functions from the original Main Menu UMG. For the items that I wanted to change out, in our case the text images that I am using for the different languages, I binded the images to a Texture2D variable. On EventConstruct in the second UMG (the one I wanted to make the changes to) I grabbed a reference to the pasted Main Menu UMG and set the specific images there. Changing out the different UMGs was quite a task, but I am able to swap between the two UMGs by selecting a language from the Main Menu.
I hope this helps in some way. If you would like, I can take screen shots of any of the parts of the process or UMGs that I am using