Hyperlinks (created with the Link tool are very simple, and don't provide the features you are looking for.
However, you can get what you want using a Button form field.
A short explanatory text would be the short description which you set in the field properties dialog. This is the mousetip help you know from many other places.
If you want a popup with a series of links to follow, you would use some little JavaScript, and with the app.popUpMenuEx() method, you have the full range of possibilities for a popup menu. Check the documentation (part of the Acrobat SDK, downloadable from the Adobe website) about which event to use for the popups.
If you want to be more verbose with the stuff popping up, you would show and hide additional fields, one of them a Button field where what you want to display is a PDF and used as icon; you may overlay that with other button fields for links and other actions.
Hope this can help.
Max Wyss.