I get this problem too when trying to overlay any text onto a rectangle. Although clear in indesign, once it's exported to an interactive PDF (as a font / converted to curves), it vanishes!? I've also tried putting the text onto another layer, that's not helped either.
It's a limitation of PDF that any interactivity will always be at the top of the stacking order. Thus you can't have text above a button, for example. You need to make the text into a button, then you can put above the other button.
Steve Werner has given you the correct answer.
Your buttons can easily be put on the master page. And will interact when exported as PDF.
However, the text will disappear when the button is pressed.
You can make the text a button with no action that will be above the button that provides the color. But that will only allow the text to be the active hotspot. The object below will only be active where the text isn't.
My own solution would be to make the text and color a group and then make that the button.
HOWEVER, you have mentioned using the Click State or Rollover State to show the color change. Be aware that those states can only be seen on computer screens with mouse prompts. They don't work on tablets or phones. Only On Release or Tap will work on tablets or phones.
Even then, you may find that the buttons don't work at all—click state or tap.
I just had a problem yesterday with three buttons created in a PDF to show/hide layers in the PDF. (Buttons created in Acrobat.) They work fine on my computer running Acrobat or Reader. But didn't work at all on my iPad, even when viewing the file in Reader.
My own suggestion is to give up PDF and consider FXL or the Adobe Publish Online service found in InDesign CC 2015.1
Thanks for your help guys! I got around it in the end by creating a jpg button (white text on black rectangle) in Photoshop and just importing it to create the button.
Glad you got it to work out. :-)
Not sure if you saw Sandee's post but you can also maintain the ability to have a rollover state by grouping an InDesign text box with your button made in InDesign, then making that group a button. That maintains the ability to edit for rollover states, and you don't have to leave InDesign to do it.