1.) Not all bobbin cases have oil pads. my Bernina nor my Elna do.
2.) That lever is what makes the walking foot walk. I suspect there is a spring assembly that drives it down, the needle thumbscrew pushes it up. Unlike my Bernina that goes around the thumb screw and gets driven both up and down.
3.) We all make mistakes. I just found out I have been threading my Bernina wrong for the last five years. It still worked, now it works better.
tim in san jose