Being from the UK (living in the US now), I've never used the term 'hey guys', with my English accent it would sound like I'm being a fake or trying to hard to be hip.
Likewise, there's not a chance in hell I can pull off "hey y'all", well maybe if I was wearing a cowboy hat... :)
In any case, I use "Hey peeps..." (peeps -> people), which doesn't offend people (afaik).
Really? I'm from the UK and I find "hey guys" and "you guys" to be quite common there. Maybe it's a generational thing - I'm sure it's something we picked up from the U.S..
The idea that it's sexist or problematic to address a mixed group as "guys" doesn't quite seem to have crossed the Atlantic yet, but I'm sure it's coming. The U.K. is never too far behind American cultural trends, especially the insane ones.
That's the beauty of language. We can choose our phrases and words, influenced by the people of our geography. You are free to choose peeps, and I am free to choose guys, until there are laws against it (coming soon, I'm sure).
Someone can also choose to be offended or not. Apparently this has been forgotten in modern times.
Likewise, there's not a chance in hell I can pull off "hey y'all", well maybe if I was wearing a cowboy hat... :)
In any case, I use "Hey peeps..." (peeps -> people), which doesn't offend people (afaik).