Hi! I'm a second-year MSTP and I also applied to MD and MD/PhD programs. That said, I'm an international, so my options were limited. I would strongly advise against applying to both. I think you pretty much know why, as is evident from your questions. When applying to MDs, you have to be really careful to talk about your research, but not too much. If you're interested in the details of my experience, hit me up, but again, I think that MD and MD/PhD apps are quite different, and there are very few circumstances when one should consider applying to both.