67 Dart Idler arm question

I think you're making too much stress about the 67 idler arm. The only real issue with it is its cost. Tes there were design flaws that were corrected after the one year but that flaw is as much or more related to how its mounted to the K frame as the arm itself. Whether the engine is there or not doesn't really factor in to its R&R either. Most any suspension parts are easier accessed with engine removed.
There is a puller made for pitman arms. A gear puller can work there also.
Some will drive a pickle fork between the steering gear and arm but..
doing that can damage the steering gear internally.