I've followed a lot of cases and it's not that unusual, in my humble opinion.
Particularly with children in growth spurts, when they may have more casual clothes on hand: clothes that are almost outgrown but are still being worn and clothes that are larger that have been gotten in order to accommodate growth.
Lyric being the youngest daughter doesn't have a little sister to pass things down to, so it's more likely for her clothes to hang around.
I doubt this is a runaway situation. Neither girl has a history of actually running away although Lyric made a threat at some point recently. Running away is a set of skills and kids typically have to try it many times before they become proficient enough to stay away for a significant period of time.
Yes, Lyric did make a threat to run away but that alone is not outside the normal range of child behaviour. Lots of kids make the threat but either do nothing about it or hide until dinner time.
Also Iowa in the summer is garage sale land. If anyone in the family is a garage sale shopper, the girls may easily have more clothes than anyone could possibly remember.
FYI the missing posters I've seen/shared on FB and have detailed clothing descriptions.