I cleaned up a few sketches and then created it with a surface and sculpt. Also got rid of all multibody steps. I don't have the educational version or know anything about it so I'm not sure if you can open or not but I attached it.
Everyone models differently, of course. For me, putting that last feature in as a surface was easiest/quickest. It could have been done as a solid step but the sketches would have been a little more involved. I usually like lofting surfaces more than solids anyway. Less edges to control. I didn't use any surfaces elsewhere.