Well for starters, I think you need to make sure that your units are correct and in FT. Try making the X and Y something like 1 or .5 and see if that helps. I am guessing a bit, but I would think right now its trying to place it over 400 & 700 feet away from the origin of the sheet.
And yes, you are correct that when you delete the holder sheet, the view instance goes away. You could solve this by getting ViewSchedules by category rather than Schedule Sheet Instances, but the nice thing about the Viewport node is that it will get it from the instance which I why I used it initially, but it is not the only way.