We do usually put a thin balaclava for kids already at much lower temps. It covers the neck and also prevents snow from going down clothes a little.

Remember also that this is for kids.

As an adult living just south of Finland, I don't really do scarves, even at -30. I reckon many Finns probably don't either.

And shorts and tank tops are acceptable at 15C, just not for kids.

I grew up in northern mn, where temps were easily -30c for weeks at a time. I knew families that didn't believe in hats. Like they just didn't have them. Although to be fair, I think they were part finnlander, so I guess that checks...

also wearing nothing but a tank top and shorts at 20°c, it takes at least 25° for me to reach that point.