It's amazing that Night Train set that record in a 12 game season. I believe he had at least one other season in double figures. That record will likely never be broken. Teams pass much more now but they tend to not challenge top-flight corners with much frequency. Thus, anybody at the level to pick off 14 passes isn't going to get many chances.
As far as Dolphins corners, I grew up in the 80's (formative years) and (mostly) 90's (graduated from HS in 1998). Terrell Buckley was decent at times and atrocious at others (it seems like he got burned with more frequency than you would like). He was not on the level of Vincent or Madison (nor Surtain for that matter). but he was good. Don McNeal was a good corner as well (I assume this discussion is limited to CB's and not DB's in general) but I only really saw him on film years later.