How do I ask, "I thank you guys"?
For "I thank you, guys", it's the same: 'Ich danke euch, Jungs'.
Even if "guys" in English can include women? As in the British term "you lot"?
No, in that case 'Jungs' doesn't work but your proposed solution 'Ich danke euch' or 'Ich danke euch allen' do.
Disclaimer - not a native German. Simply "Ich danke euch"? "Danke allen"?
Why not Jungen?