I started in 2022, and I am a voracious learner, but experience is what I do not have, so, unfortunately, this was an unavoidable situation.
The reason is because the splines need to be in specific locations, and I need to be able to see those locations as I edit them. Unfortunately, because the splines are attached to parents themselves, I can’t even use the default Transform anymore without starting over:
These are boarding and disembarking transforms for the player character as they get off and on trains.
If you are indeed correct, and I’m out of luck (and will have to roll up my sleeves), so be it. I’ll let the topic stew for a few days, and if neither you, I, nor anyone else comes up with a solution, I’ll credit you and mark this “solved”.