WCIF/modding request king robes for child/teen fulfilled

I found a few things that might help but I don't know if they're exactly what you're looking for.

Here is child version of the beast's outfit from Beauty and the Beast, however Spooky Stuff is required to use it:
inabadromance.tumblr.com/post/161701576384/beauty-the-beast-mini-set-made-with-the

This blog has tons of objects and outfits converted from Sims Medieval:
zx-ta.tumblr.com/tagged/medieval+cc

Here is a child outfit from the above blog:
zx-ta.tumblr.com/post/158707934497/child-mf-shoes-are-part-of-the-outfit-under

Here is another medieval-style child outfit:
simsworkshop.net/resources/wiccandoves-medieval-tunics-for-kids.486/

I hope this helps!

Hey! I don't know if it's too late but I also saw this and instantly thought of this WCIF

It's still not exactly what you were looking for but it might be a little better than the ones I sent before:
historicalsimslife.blogspot.com/2018/07/ts4-polite-boy-outfit-sims-3-to-sims-4.html

Honestly the whole History Lover's Sims Blog is worth checking out for what you were looking for.