The vertical movement on the spindle is normal, so as long as the bearing feels smooth and snug in rotation just a few drops of Technics spindle oil (available from most DJ supply houses, and in the US from KABUSA.) should do it. Edit: I see you've done the oil.
The start/stop switch behaviour does not seem normal, mine doesn't do that so I think some work may be needed there. (See below)
Effectively there is a switch mode power supply (ala wall-wart) under the vent screen, so you are probably smelling the combination of some heat and high voltage. (By the way I assume that you are checking this after switching off - it isn't good for the motor system to be powered up for long without the platter in place.)
When I got mine it sounded good, but not hugely better than my SL150 MkII. So I set out to do the adjustments in the service manual (available here on VE) and after unscrambling the errors in the service manual
I found that I couldn't achieve the specified settings. I then replaced the electrolytic capacitors (only 2 actually measured really bad) and set the adjustments. Now we are hearing some good sounds
. I suspect that the electrolytics were causing poor torque, which is the main feature of the SP-15 relative to the SL150 MkII.
If you can do this yourself, or have it done at a reasonable price (for you the caps should be less than $20) I think it would be well worthwhile, and may also take care of the strange speed read-out.
Hope this helps