its pretty simple!
look at the xml code for all the hotspots. there will be a url for the hotspot that is displayed, just replace the text for your choice in gif etc. obviously ensure the gif has the same folder.
If you have lots of animated gifs going on, I could imagine it to be a bit irritating, just decide what you think is best.
As for creating the hotspots, drag and drop your pano onto "create virtual tour" droplet. There is an html file that allows you to edit the hotspots and start-up view etc. Place the hotspots this way. It will ask you to link the hotspot (only to the panos available) In the html file you can edit the xml (don't forget to save) and change the link of the new hotspot to whatever you desire.
If this sounds a bt much perhaps tryout ptp2 made by kolor