Losing the plug does not necessarily mean you are dilating. And I think some women can and have felt their baby drop most definitely! It's a good thing because you want their head on that cervix because that is what is going to dilate your cervix.
I didn't feel my daughter drop but as far as losing the mucus plug if it doesn't have any blood then it could still be a couple days to a couple weeks until you go into labor. As for dilating I lost some of my mucus plug recently and my doctor said I was either a finger tip/not really dilated.
I never felt either of mine drop but I did notice a pretty big difference visualy especially with my first.