In this world, only nobles have family names. Regular people just have a given name. That's not too different than what we see in some European societies in the middle ages.
You skipped the:
then you have the “call by name is only for very close relationship” …
Which means the
onlymain way to call them is either with: nicknames, aliases/titles, add prefix/affix to it, etc. -- Kinda like how the adventurers refer to him as [Herb].
But it's still kinda iffy, since they introduce themselves with their given name (heroine did at the start); plus
1. Nicknames tend to be what close relations call you.
2. Aliases / titles would need fame, tho guess you can come up with your own.
3. Prefix/affix is more cultural -- aka mr/ms/mrs, sir, Jap's -san, -chan, -sama, etc.
Which, with only having one name, is kinda redundant(?).
Anyways, lol the clothes, most of them look modern, so no clue how they'd make it by hand (mom's supposedly a weaver).