Diagnostic. Remove and replace starter, check flywheel by turning over engine 1 full revolution, all teeth present on flywheel.
Fix horn, remove steering wheel, clean threads, replace stripped bolt with longer head bolt, replace other two bolts with longer head bolts. Remove and install new ignition switch. Remove headlight and check for springs on adjuster, which are present, adjust headlight adjuster screws so they are set against springs. Will need adjustment at night. Test drive.