Off topic:
Wow, I never noticed that before -- awesome!
Well, I probably can't help you very much with your animation questions, but I can make a comment or 2. You know that Inkscape doesn't support animation yet, that's why you're exporting, right? The only program I know that can do vector animation is
Synfig.
It does appear that the batch export exports selections rather than pages or anything else. Although I have not tested it yet. I also don't know what happens on the other side of the export -- iow, is each selection output in its own layer? Or are all the "frames" or selections just stacked up on one layer? Or do you get a separate image for each selection? Out of curiosity, do you know what you'll use to do the animation?
This is difficult when I use glowing effects or effects that expand because the "Selection" tab always wants to mess everything up.
I'm not sure exactly what you mean about the "selection tab" messing things up. I think you mean that those "frames" with a glow effect or blur or the like, will be larger than those without. But as long as the export only looks at selections, and as long as you have them all aligned exactly on top of each other, I think it should work. The one factor I'm not sure of is page size. If your page is the size of the smaller selections, so that the glow or blur falls outside the page border, it may not show up in your finished product. I don't know if the exporter only deals with selections, whether it completely ignores the page border....or not?? My guess is that you should make your page size to fit the larger glow/blur selections (or larger).
I'm not sure when Inkscape is set to support animation? I think I saw somewhere about Inkscape 1.0.....but that sounds so long to wait, lol.