With her altered level of consciousness, the drugs were already absorbed into her bloodstream. And forcing someone in this situation to vomit is far more likely to cause them to aspirate or choke and die than it is to help them. Forcing emesis is almost always a bad idea. In situations where it might be warranted it should be done safely (e.g. 'pumping the stomach') to prevent aspiration/choking. However, as I mentioned earlier, it would not have made any difference if the drugs were already absorbed.
Like many here, my initial thought was also that Lawrence won't go through with the plan if Eleanor dies. The look that he gave June at the funeral was chilling. I'm not convinced he won't change his mind.
I never thought of that about Emily. It would be really sad if that were true as she is the best part of the show IMO! Alexis Bledel would have been fantastic as June.
Although I have no doubt Samira Wiley would also have done well as June, she has such a lovely genuine smile that lights up her face and I don't think we would get to see that as much if she were June. She also has a presence that I don't think was intended for June, who seems to be a meeker and weaker character. But again, she is such a great actor that I'm sure she would be able to pull it off - it just wouldn't be the same June that we know now. Maybe if Samira was playing her, I wouldn't dislike her so much.