Liza, don't sand if there is a young child in the house and you have paint from before 1972, as I said in my original post. I doubt that there is anything about switching between oil and latex paint that is causing the problem. And the stripper will work on both. But who knows what has happened to the walls over 86 years??
Unfortunately, there really is not a good answer. The stripper is really the best of many bad choices. I don't know where you live, but I strongly suggest leaving this for the summertime when you can work with excellent ventilation. And be sure to keep the toddler out of the work area and away from the chemicals.