thinking really abstractly, i'd think that it'd be less about identifying who the andalites are than which morphs they're most likely to be caught in. in fact, where on earth would six grounded andalites be caught looking andalite and why would it make a difference to identify and capture a specific member of the group? (well, okay. identify and kidnap the andalite equivalent of 'jake' and see how quickly things deteriorate... but still. a hostage is a hostage.) i don't think that dossiers that include photos/videos of andalites would be useful to the yeerks unless those andalites made it off earth and needed to be identified later- after, say, yeerk conquest of earth and a subsequent attack on the andalite home planet. then, it might be about revenge, but it'd have little to do with tactics.
that being said, v1 always seemed to think further outside the box than most. i'm intensely surprised that she didn't earlier conceive or investigate the idea that the bandits might be human. or not andalite. (but then, seerow's kindness and andalite arrogance would make the scenario so unlikely to begin with... thanks, mr. ellimist.)