Two things to try...
1. Add the fade to the slowed clip after applying the speed change.
2. Don't program individual track fades. Instead, click the SEQUENCES tab at the top-left of the bin. Right-click on Sequence 1 and click on EFFECTS.
If you don't see a sequence tab, click the + sign on the Sequence tab that just above the timeline, to add a new blank sequence. 
Choose the Transparency effect and plot a fade. Set the Opacity slider to 100%, then drag the red cursor to the right until it's near the end.
Click the small green + sign to set a keyframe. Then drag the cursor to the very end and set Opacity to zero. That will automatically create a second keyframe.
The horizontal distance between the keyframes determines the speed of the fade. Keyframe dots can be dragged. When done, the graph should look like this...
.
All tracks will fade at once.