"all of you" vs "you all"
Solution 1:
“You-all”—also occurring as “y’all”—is a second-person plural pronoun that occurs in some regional versions of US English. It is used by some speakers to eliminate the ambiguity caused by the Standard English “you”, since “you” does not differentiate between singular and plural.
“All of you” is a noun-phrase that may be used in Standard English when the ambiguity of “you” by itself would be confusing or misleading.
In most contexts “all of you” would be considered the correct phrasing. Some listeners or readers perceive “you-all” to be incorrect.