I'm assuming 'Zuhausys' is a German equivalent of 'the homies' considering it contains the word "Haus".
Correct, it is derived from the English homie and mainly found in Internet communities that use a lot of "Zangendeutsch". Irl people would look at you funny if you used it.
In spoken slang people often use "Kollegen" (colleagues) or "Kumpels" (buddies) to describe a group of friends.
I mean basically anything can, there was a time in the early 2010s where the word "Atze" came up as a way to say homie, which was attributed to some rappers using it. Funnily enough the term came from the 1700s iirc.
Yes, similar, maybe 'zuhausys' would be even more obscure.