You actually have 4 viewports which could be part of the confusion, if you turn the "defpoints" layer back on you will be able to see and select the other two, though they are on a layer that is turned off they can still be selected by double-clicking inside the area they contain. I am guessing your problems are due to this because by double-clicking in the layout the viewport that becomes active is not the one that contains the geometry you think you are seeing in the vieport, use zoom extents when the viewport is active and you should see the geometry appear twice. The next thing is that there is nothing in model space that would be really seen at a scale of 1:50 the rectangle is 774 kilometers wide so you would only see a potion of it at 1:50, and the two text items are only 5mm high so at 1:50 they would be 0.1mm on paper.
I would guess that if you can delete the excess viewports that would solve most of your issues.
PS everything else looks ok your units and paper layout sizes are good
