I am wondering about how plant based eaters get enough ALA, DHA, and ELA in their diets?

Oil is not heart-healthy, it damages the lining of your arteries. Here is a great link by Dr. Essy which talks about how bad oil is for the heart, as well as omega's. The short answer is, yes. You get plenty on a varied, whole foods, low fat diet.  If you are unfamiliar with him, he wrote Prevent and Reverse Heart Disease and is a world renowned doctor -- one of the few who changed the medical opinion that heart disease is reversible. He's saved so many lives.