Posting in the current year BS/MD discussion thread will get more response.
If your clear about medicine there is nothing wrong with UR path. But appears you are more inclined toward regular UG. You are not going to be wrong and still you can get back to MD path and also can cement your desire.
Both your 2 specific questions are not to be worried. No one knows what % gave up BS/MD and could not get back to MD. It does not matter that stat. If you are still interested, you should be able to get back to MD. I know a case who gave up NJIT/NJMS and later finished MD in Columbia and doing residency now.
Always there are going to be outliers. You are capable and you can do whatever you want as long you continue your interest and work.
Covid-19 is not unique to you. So it does not matter how the admission process will work. Things will evolve and it should impact or aid every one in the same way and not just for you.
You can PM current UR BS/MD students and check if it worth or go with your top UG.
There is a student whose father is a Physician also in UR in 2016 cycle. Search every year results thread and you can get at least few UR students.