I suppose they could have extra clothes for forest hikes or something, but we can keep that separate from their usual wear. The halflings wouldn't use the boots, at least. Or maybe they are intentionally given no extra clothes for going through the woods in order to toughen them up? Still, if you really want them to have a pair of pants and boots for special purposes only (like the woods), we can put that in.

I see what you mean with the leotard bit, but it is an acceptable break from reality, in my opinion. I figure, we already have lizard children and the like running around, what's one more break from realism? If you still don't want the leotard, we can have them dress in some kind of training skirt and short leggings for the appropriate purposes.