Burner, a bonafide Southerner just says "y'all". Beware of imitations Whether it's 1 or 50, y'all covers the numbers. We would only use all y'all when referencing people from foreign lands, like New York.
Actually, All y'all is a common phrase amongst our neighbors in the Great State of Texas. Many do consider them as having a foriegn language. I think that secretly they consider themselves to be a soveriegn nation.
Wonderful folks with a great zest for everyday life.