I seem to have fixed this problem—I’m running InDesign 8.1.0.419 on 10.11.1—for now at least, and here are the steps I followed:

– Installed the Legacy Java files (ID still crashed)
– Started Photoshop first (for some reason helped ID get past the splash screen, but still crashed shortly after startup)
– Turned off El Capitan’s hide menu bar feature (a shame, because I was liking it, but this bug is apparently affecting CC as well)

Hope that helps someone.