I'm not familiar with Adobe Flash neither with Adobe Illustrator.
Because FFDec has no drawing tool at all, I'm using Inkscape for drawing modifications. It's a free tool so it may be not as refined as commercial tool. I had to watch some youtube tutorials to learn how to use that as many features are not obvious. The disadvantage is that I have to export drawing as SVG from Flash first and then to import it back to Flash file because Inkscape is not any integrated to Flash.
Regarding HTH2beta, I have no workaround for tedious manual image replace frame by frame.
I know that it depends on individual view, but I don't see HTH2beta worth of any effort.