These are tutorials for making a GIF from video.
The question posed is how to edit an existing GIF.
I've been searching the web too, sans any luck.
Seems like you should be able to edit a gif the same way you create one. I just opened a gif I pulled off the web, and opened it in PS. All the frames were shown as layers. I could then click on any of the layers or frames in the frame animation pane and update edit them. In the pop up menu on the timeline you can select "New Layers Visible in All Frames" if you want to add text that will show in all the gif frames or you can editing one by one by unchecking that selection. Have you tried editing a gif, and what issues are you having?
I had trouble knowing how to open and correctly save the modified gif.
Stumbled through it, with your note, and seem to have figured it out.
Thanks very much for the help
Thanks that was exactly what I was looking for!! (the new layers visible in all frames option)