Also, while I’m asking, the original doors have crystal door knobs with Art Deco style panels that are tragically painted over—anyone know what this panel is called or where to source it?

The stops (as what you are asking about) would be called Roman Ogee, or just Ogee. Since you have painted doors I wouls suggest Trustile Doors

You have recessed panel doors but they are not shaker, since they have that detail.

That part of the door frame, the stiles (vertical) and the rails (horizontal) that hold the panels in can have various profiles on the inner edge. This is called the "sticking":

The new shaker door you show has Square Sticking.

The doors in your house might be Ogee but they seem to have an extra curve, so might be Cove and Bead Sticking.

The three dimensional panels might have Anaglypta or Lincrusta, which is a typed of embossed wall covering on them.

The triangular plate on the door is called an escutcheon, backplate or sideplate.

The triangular plate/escutcheon/backplate can be removed (along with the crystal knob) and put into a pot of boiling water. The paint will peel right off, should you wish to remove it. Use a wooden toothpick to remove paint from the crevices. This is one of the easiest restoration activities out there.