Q: Where to find the Keyframe Velocity or Speed Graph on Motion 5?

call-up the keyframe editor, cmd-8

http://help.apple.com/motion/mac/5.2/?lang=en#/motn14749268

and for ease-in/out etc. edit the curves

http://help.apple.com/motion/mac/5.2/?lang=en#/motn147486cf

To the right of the Keyframe icon in the inspector window, there is downwards pointing arrow, with brings up a dropdown menu, where you can find the 'Show In Keyframe Editor'