For Brazil, level 2 seems exactly right.
> ” Level 2: Casual acquaintances. Used more widely for neighbors, family friends, or community members you vaguely know, but typically not for an absolute stranger.”
I would specifically add to he list of examples your school teacher when you are a child and the parents of your friends, seems the most common usage for it.
Slightly related "What kind of uncle am I?" by Reymond Chen https://devblogs.microsoft.com/oldnewthing/20090427-01/?p=18...
I grew up calling every stranger uncle and auntie in India. My British roommate in Delhi was a bit taken aback when I called our landlady "auntie".
In Spain, tĂo and tĂa are used with friends, depending on group/region. Calling a stranger that? Not friendly, but neither openly hostile.
On the other hand, it's common to refer to third persons as "un tĂo" or "una tĂa" the same way you'd say "some fellow" in English.
This is also common in the Italian/Greek/Indian etc. American subcultures. Immigrant cultures take their time - and sometimes never - in absorbing the larger anglo-saxon culture into their own.
In Tamil (and South Indian states), it’s common to call elders appa (dad) and amma (mom). Mama & mami is user typically by a small sect of so-called upper caste people.
In India, at least in Hindi, there is uncle and aunti for strangers and the blood relatives have their own words (mama - brother of mother, masi - sister of mother, bua - sister of father, etc). Whether these specific words are used for non-blood relatives is kinda specific to the people in question.
So I wouldn't say there is any implicit kinship there. If I call a random stranger "uncle" then there's no real meaning to it. If I call him "mama" or "chacha" then that would be implying a relationship.
Speaking as a Bengali from India, we are definitely level 3. Also, this extends to grandfathers and grandmothers.
For the USA
> Level 0: Blood relatives only. “Uncle”/”Auntie” is strictly for real uncles/aunts (by blood or marriage). No fictive use.
This is definitely not true for children in the USA. I believe it is common (or for sure it was common) that children use Aunt/Uncle for close friends of the family.