Has El Capitan Disk Utility Removed Encryption Options? With Mavericks I would unlock an encrypted disk using "Disk Utility", but in El Capitan the "Unlock" button isn't there.
No, just moved them.

Method 1:
Disk Utility > Menu > File > Unlock
(Embarrassingly I found this item after posting the question and using command line option to unlock the drive)

Method 2:
Command line, open "Terminal"
hdiutil attach /dev/diskXsY
Where X,Y are system specific numbers like 1,2,3.