The first picture is a 99 that came to me with a motor and foot control, the light is wired into the block under the motor. The second picture is a motor/bracket from a 15-90. I put the 15-90 motor onto the 99 and the belt appeared to line up fine ( I didn't take any measurements) and it moved the machine just fine.
From what I've read elsewhere I think finding one of those knee levers might be difficult and/or expensive, not to mention the rewiring problems. I've never seen under one of those knee lever covers, so I don't know how hard it is.