starter stays running in on position

Most often... the column is lowered for inst' panel R&R. In that, the neutral safety adjustment is lost, needs readjusted. That doesn't cause starter run on though. Just neutral safety hunt. So... You have 2 separate issues.
If the yellow wire at starter relay has power when ignition switch is in on position, look at a white plastic harness connector from ignition switch under dash. I've seen them melt and short before but don't recall in such a way as to feed the yellow. I haven't seen it all though. Good hunting.