I have the adapter that is supposed to plug into the Optiwiz and it has 4 pins... there are a total of 6 connections coming off of it.. The boards on the Happ 3" trackball have 2 4pin Molex joined to one 8 pin molex... Where do the .187 terminals plug into since there are none on the trackball or its original harness ?
That sounds like you got the
mouse button cable.

One end of the mouse button cable has 4 pins in a row (0.1" Dupont female, connects to ground, L, M, R below the chip) and the other end has 0.187" female terminals for ground (the 3 daisy-chained connectors), Left, Middle, and Right mouse buttons.

The cable you need is the
Trackball Cable for Opti-Wiz™ "No-Solder".
I'm not sure if you ordered the wrong cable or if Randy accidently shipped the wrong one.

ALSO, how do you obtain the power that it says is needed.. I thought the power was had through the USB plug??
With the Trackball Cable for Opti-Wiz™ "No-Solder", you connect 5v (red wire) and ground (black wire) to the pins in the upper right corner of the pic above.
Data lines for X-axis (blue and purple wires) connect to pins A and B in the lower right corner of the pic above.
Data lines for Y-axis (green and yellow wires) connect to pins C and D in the lower right corner of the pic above.
If an axis is reversed (i.e. moving the trackball to the right moves the mouse cursor left), swap the data lines for that axis. (i.e. blue and purple wires)
Scott