Thanks to your explanation I managed to fix the detail view's layout and I am confident I can get it to display whatever I'm planning to add.
The reason I am looking for the file used to display the original edit page is because I am not that code savvy and after several hours of trial and error I can't really get it to work like the default edit page. (can't seem to get all the info back on a single tab and I also couldn't find any documentation on changing the type of user input such a scalable text field or a drop-down with integers.)
So far your leads have brought me a lot further, so thanks for that! If the remainder of my problems would require more personal attention I am willing to make an arrangement to turn this into something mutually beneficial.
Again, thanks so far.