The capacities can be reported as terabytes (decimal) or tebibytes (binary).
4TB = 3.63TiBhttp://www.google.com.au/search?q=4E12+bytes+in+terabytes
ISTM that you are correct in your thinking regarding the Bluray player. It does appear to be limited to 2TiB capacities. You say that the 4TB drive "shows as 2TB with 1.88TB used". In other words, the player is saying that the drive has 0.12TB free. That's about 120GB. You state that the free space reported by the laptop is 118MB. Did you actually mean 118GB?
As for why your 2TB drive has assumed the identity (?) of your 4TB drive, we would need to examine sectors 0, 1, and 2 with a disc editor (eg DMDE, freeware) in readonly mode.