Fade out and fade in multiple text captions

You can use Effects as alternative. You'll need twice AlphaFromTo and once Alpha. Here is an example for one text container. Overlapping a little bit avoids flickering:

Using JavaScript you could do this. Consider the following code...

$("#textc").fadeTo(3500, 0.3);

In this example - you have a SmartShape object with the name of  "text" (the 'c' must be kept).

The 3500 is the time in milliseconds which is the duration of the fading. Lower the number to fade faster.

The 0.3 is a value between 0 (invisible) and 1 (fully visible) - so figure about 30%.

To come back to full black - change the  0.3  to  a value of  1.

If there are no triggers to set these off - you will need some timeouts.
Here might be an example for Caption 1.

There are three blocks - if I understand your example correctly...

1. Show the caption at 8.4 seconds (8400)

2. Partial fade out to 30% at 16.6 seconds (16600) this action takes a half second (500)

3. Fade back to black at 45 seconds (45000)

setTimeout(function() {
cp.show("caption1");
},8400);

setTimeout(function() {
$("#caption1c").fadeTo(500, 0.3);
},16600);

setTimeout(function() {
$("#caption1c").fadeTo(500, 1);
},45000);

If it helps - great!

I also realize this may not be compatible with the way you have you project currently built.